Air carrier Flight Attendant reported a fume event during departure taxi resulting in a ground gate return. No local maintenance available ultimately resulted in flight cancellation. During flight delay flight attendants physiological symptoms worsened resulting in sick and fatigue call.

Narrative

In ZZZ before Aircraft X to ZZZ we had Maintenance out because none of the PA's were working. The pilot to cabin and F/As (Flight Attendants) wasn't working and you could not hear any announcements from the front or back PA. Maintenance was able to turn the volume up on everything but the Aft PA so as A I was having to do the B's job as well with making baggage announcements etc. as well as doing my own duties up front.We landed in ZZZ uneventfully and boarded up to leave. After doing my demo I did my walkthrough and about 3 rows from the back I suddenly smelled a strong; acrid smell...like something electrical burning. I asked the B if she could smell it but due to being stuffy she couldn't smell anything. I immediately called the C back there and she could smell it within 3 rows before walking into the back galley too. I called the pilots who were dinging us for takeoff and they immediately stopped and said they would call back. The coffee pot was not on and there were no blown fuses. By this time our eyes were all burning and I was starting to experience a headache and nausea. We has a commuting pilot come back who told us he doesn't smell well but he could even tell it was a hot smell. I called the pilots again to report that and the burning eyes/headache and they chose to go back to the gate. Maintenance was an hour away. Dispatch and Ops decided to take everyone off the plane as it was obviously not going anywhere. Within minutes the pilots had been given a hotel. I called scheduling at XA:06 to inquire if we were going with them as they thought we were still taking this plane out. She told me she would talk to a supervisor and pilot scheduling and call me right back. By now my eyes were blurry and I had an extreme headache and nausea. At XA:18 I missed a call from a number and assuming it was scheduling I called it back. The person said they had just called and started asking questions about what happened etc. I still thought I was speaking to scheduling and when he asked if we had symptoms I said our eyes were burning bad and I had an extreme headache. He asked if we needed medical attention right then and I said no...still thinking they were calling to send us to the hotel. He then said oh I'll transfer you to Scheduling now. Someone picked up and told me they were having parts for our flight brought in and we would be taking it to ZZZ1. Maintenance had not even shown up yet to check the plane. I again told her I was feeling very unwell and she said she would call me back. Maintenance arrived a few minutes later and said it sounded like a ballast fire above the aft galley in the ceiling. We got off the plane; the pilots left and at this point I couldn't see more than a few feet in front of me; my eyes were burning and watering; I was sick to my stomach and my head was pounding. I told the other girls I was going to call out fatigued as I needed to lay down now and I couldn't see even my phone by then. The new girl was afraid to call out and NAME decided to stay with her even though her eyes were burning and she was getting a headache as well. I called scheduling @ XA:29 local and asked for a supervisor. NAME came on and I told her we had an incident and I was not feeling well at all and called out fatigued. She snapped at me that I didn't need to speak to her I could have spoken to anyone and I explained I had already spoken to scheduling 2x and had been given incorrect information and I was REALLY feeling badly from the burning in the back galley. She informed me of my DH (Dead Head) today to catch up with my crew and told me I would have to wait for a call about a hotel and hung up on me. At XA:41 local with the help of the other F/A's in using my phone I called the COSA desk and NAME1 was wonderful; she told me someone had booked me at the [hotel] and to call the shuttle. I did; and was told I would need to put a c/c down; I called NAME1 back at XA:57 local and she spoke to the hotel and took care ofit. I flushed my eyes with water for 30 min and took pictures of how very bloodshot they were. I went to bed with an ice pack on my head trying to relieve the headache. I was up all night long with the headache/ eyes burning and threw up twice. At XB:17 I was able to finally sleep for 4 hours. The burning is still there but has lessened; as has the headache. Before going to bed last night I called the number that had called me while on the plane asking me questions. I found out I had spoken to NAME2 of Company Communications System. I spoke with him for a bit and explained I was so out of it I thought I was speaking to a scheduler earlier. He told me if I got worse overnight to call him back and they would get me to the ER. Otherwise to call ZZZ1 inflight this am to fill out a [form]. I had spoken to the other two FA's right before that and told him they were experiencing the same symptoms. He called them back. I filed the form with NAME a few hours ago and I still need to file the fatigue report and safety report. I've also left a message for NAME at the union to document the safety issue.