No phones, no refunds

I placed 2 orders for Google Pixel 4a 5G through the Xfinity mobile website on April 11, and the money was withdrawn within a day. It's almost 3 months later, and I still don't have the phones I paid for. First backordered, then back in stock, now not even available on the website. Over the past month, I've chatted and been on the phone with customer service multiple times, been promised twice that they would ship within 2 days, and nothing happens.

5 days ago, I gave up on waiting and asked for a refund. I was on the phone for 1.5 hours, talking to 3 different agents while they chatted with Tier 2 and Tier 3 customer service. Once again, I was promised resolution. My orders would cancel and I would receive my refunds. It's been almost a week now, and guess what? Orders still don't show as canceled, just "not yet shipped", and I still have no refunds. 

Chatting and calling the support line is not working. What else can I do?