Flight Attendant reported crew communications were improper after the flight began an unexpected descent due to an engine failure.

Narrative

During Inflight Service I was working in first class delivering meals. The First Officer called and asked for his and the Captain's meal to be placed in the oven. I informed him that we would call back when finished. I would account for maybe 5 minutes later the first class galley position [Flight Attendant (FA)] A and I noticed that all the ovens on the right side turned off and so did the power on the right side of the aircraft. As FA A and I prepared the crew meals for the cockpit the ovens had turned back on. With a couple of failed attempts to reach the cockpit; FA A had thought to just call them back in a few minutes. Moments later the cockpit called back and the Captain informed FA A that we had 20 minutes before we land and that due to right engine failure; we will be diverting to ZZZ. Once FA A hung up the call and proceeded to inform the Purser and myself what was relayed to her from the Captain the phone rang again from the cockpit. FA B; the purser answered the call to which she was informed we only had 10 minutes until landing. The purser relayed this information to FA A and I then tried to contact the rest of the crew. She made a PA for 'crew members to pick up the phone.' I immediately told her to contact the crew via all call on the phone and not PA. The crew members then called up to door 1R and told us that they noticed we were descending around 22;000 ft. and were concerned. I immediately cleaned first-class meal trays; and drinks and ensured all performed all safety checks then sat in the jump seat. Moments later we landed safely in ZZZ.