Meta says i sent back empty box

Has anyone dealt with something like this before?I bought Meta glasses, but they wouldn't connect to Bluetooth. After trying everything, I returned them and bought a replacement. A month later, I noticed I still hadn't received my refund, so I contacted Meta.After investigating, Meta told me they received an empty box. The problem is that they never informed me my refund was being held, and they never contacted me to say there was an issue with the return. I only found out because I followed up myself.I've been stuck going back and forth between Meta and FedEx ever since. The package weighed 1.5 lbs when I shipped it, and I provided the full tracking history showing it was delivered. The glasses haven't been returned to me, and nobody can tell me where they are..To make matters worse, my credit card company says it's beyond the 60-day dispute period, so I can't use buyer protection. At this point, I don't know how else to prove that I returned the glasses, and I'm not sure what my next step should be.