Air Conditioning - AC Leak

I have a 20 year old ac unit and am on the ground floor with a neighbor who had a problem with his ac leaking into my place in the past.

There was a little a/c condesation dripping inside my place yesterday and right near the unit in my ceiling. I turned off the a/c immediately. Then I go outside and try to unclog the a/c pipe as well as my upstairs neighbors with a shopvac cause the pipes are right next to each other. Got some but not alot out of each. I also tried to clean my ac pan but couldn't find it and other people who worked on the unit in the past have said it's extremely tough to access.

Leave and then come back to my place a few hours later and find the condesation now is a full fledged leak. Some of the popcorn ceiling could be peeled right off. Try calling my service contract ppl and ofcourse they're not in. Then I take out my dehumidifier to dry out the ceiling overnight.

Wake up this morning and find the ceiling to be much worse. Much more of the popcorn can just be peeled away. Then I decide to build a plastic enclosure to isolate the leak from the rest of my place to dry out faster as well as determine if it's my a/c or his upstair neighbor's a/c.

Then I find my digital temp/humidity gauge that I couldn't find the previous day. With the a/c in the my place still off I have determined that humidity levels are significantly increasing whenever the neighbor's a/c is on and decreases when it's off.

I contacted my neighbor and they won't do anything till I get my a/c looked at. (Don't even ask about the idiotic condo board people).

Is there anything else I can do to get this leak taken care of on my own?

Need to find where leak is coming from

Have you looked at the outdoor condenser unit ??? See id the lines have any ice on them . The big line copper line cold and wet the small copper line warm like. ON his unit. Any way you can find out if his air filter is clean?????