Working in Philly, living in NJ. Did I pay PA state tax?

This tax season is so confusing. I live in NJ, work in Philly, and I have 2 separate W-2s from my employer. Box 17 on the PA W-2 shows that $1283.76 was withheld from my paychecks for state taxes, and $17.24 was withheld on my NJ W-2 in the same box. I have been trying to file on MyFreeTaxUSA, but whether I try to file in NJ or PA, it keeps showing a balance of $800+. I tried contacting support, and they told me to file in my state of residence (NJ) and that NJ and PA have reciprocity, so it should be fine. But when I file in NJ, it's saying I only paid $17.24 in state taxes, so I owe $800. There's a section to fill out for "Taxes paid to another state," which balanced everything out. However, support says that's incorrect, and that just because my employer withheld state taxes in PA doesn't mean I paid taxes in PA. I'm now completely lost. I tried starting just a PA return, and that was saying I would owe over $1,000, so where the heck are these taxes going lol. Please be kind, I worked at the same job for years before this, so my taxes have been very simple up until now.