Air Carrier First Officer reported a Dangerous Goods cargo weight discrepancy during pre-flight. After multiple attempts to resolve the weight difference the Hazmat cargo was unloaded which resolved the discrepancy.

Narrative

Upon arrival to the aircraft during preflight; we saw that we had two preliminary dangerous goods listed. Just prior to push; we received a final summary dangerous goods. I asked the Captain (CA) if I could acknowledge it. He approved; I acknowledged; and we received our final weights. Around this same ground crew asked if we were ready to release the brake and they could capture. The CA released the brake told them to standby. I brought up the silent push; got a thumbs up; sent for silent push; received clearance to push; and the CA asked if we only received one final summary dangerous goods. I said yes; and showed him the summary along with our final weights. He verbalized that the date stamps on the final summary and the final weights were different. I verified that they were different. The CA asked me to contact Ramp to hold the push and I did. We had a quick discussion about the DG (Dangerous Goods) timestamps. He asked me to doublecheck DG portion on timestamps. At the same time; CA asked the ramper if there was one DG now or two and if there was another summary. The one we had was for 33 pounds of dry ice. The ramper stated that there was only one but that it was for 38 pounds (33 pounds of dry ice and about 5 pounds of stuff). We now had more of a concern that the timestamps and/or paperwork may be incorrect. The CA asked me to contact Ops to ask if there were now only one dangerous good or if we were missing a separate summary since the ramper was now stating a different weight and our summary had a different timestamp. Ops spoke with the ramper to determine if the paperwork was correct and after that neither Ops nor the ramper could determine the accuracy of the paperwork/load. The CA contacted Dispatch while Ops and DG loader conferred and I requested and received another Final summary DG summary/final weight manifest to see if the paperwork now matched. It did not. Ops informed us they were pulling the DG and we would receive a new DG summary. We kept the passengers and FAs informed of the delays; received another final summary DG (with no DG) which we acknowledged and received another final weights. I noted that per the FOM; a DG load change requires a report and recommends submitting a report and told the CA. The remainder of flight was uneventful and the CA called the ZZZ Chief Pilot upon arrival to ZZZ1. The Chief Pilot said to fill out a report.