Paraguay Visa Overstay

On April 5, I flew into ASU airport and bought a multi entry visa and expiration date says July 5. On June 10 I took a same day trip to Posadas from Encarnacion. I went back to Asuncion and went to migrations at the end of June to do a 90 day extension, and the guy said it wasnt needed because when I crossed on June 10th I was given another 90 days, and said I was ok until Sept 10. I pointed out several times the multi entry visa at airport says expires 5 July and he said no problem dont worry about it. I'm not sure if I've actually overstayed, but if I have what do I have to do when exiting or was this guy right? I want to go to Bolivia in the next few days and cross back into Paraguay.

When you crossed into Argentina and then back into Paraguay, did they re-stamp your passport?  If they did upon re-entering Paraguay, then you have another 90 days from the date they stamped as your new entry date.   If they didn't then you've overstayed.