Newsflash: I’m purchasing my first house, and close tomorrow, but ran in to weird issue at the end

I am purchasing a house that’s older (1953), and there’s some electrical issues (no grounding, no CGFI compatibility, loose conduit, etc.) we requested to be fixed/addressed during the due-diligence period that the home inspector found. The seller also didn’t provide access to the electrical box during or prior to the home inspection, which meant the inspector couldn’t access it.Since time has gone on, and the due-diligence period ended, they have still not fixed what we asked them to, even tho in the terms they said they would. The listing agent keeps saying that the work was completed by a licensed electrician, but wouldn’t provide his name or phone number. We went back out for a second home inspection with the same inspector to make sure the work was complete. It wasn’t. Access to the crawl space and amp box were given, but the home inspector isn’t an electrician, and probably didn’t know what to look for as far as the arching went.My agent has been reaching out to the selling agent multiple times to see if the work has been completed, but never an answer, so my agent went back to the house with our own electrician (hired off google). During the inspection the electrician was conducting, he opened the breaker box and found signs of arching and melting due to a very old and worn amperage box. It’s going to cost, by his estimation, about $6,000 to replace. The electrician also said he could not, in good faith, keep the electricity on because of the fire hazard, and subsequently shut it off.So we told the listing agent, and they freaked out on us; saying it’s our fault the arching happened and that we were responsible for the damages. The listing agent even called the electric company and DEMANDED (cussing and yelling) they go back and turn the electricity back on. Listing agent said we were trespassing and had no right to go back and inspect the property again. They also said that it was outside of the due diligence period, which is correct, but they never provided access to the amp box in the first home inspection; almost like they were trying to hide the melting and arching.The listing agent also just sent my agent an addendum stating that since we turned off the power, that when we do a walk through, they are not liable for anything. However, the electrician had to turn the power off because he said the way it was, it could cause a serious fire.Are they allowed to this? what sort of options do I have in order to cover my ass in case I need to take them to small claims court, or if that’s even an option since we’re out side the due-diligence.It’s a weird issue and I’m just trying to see what my options are. It seems to me and my agent that they knew about this issue, and wanted to hide it as long as possible.I literally close tomorrow, and all of this culminated TODAY.Should I still sign the closing paperwork and wire the money still?Should I reject the addendum, or ignore it? they legally have no way out of selling me the house now, so just wondering what I should do there also.