If you have access to your old phone records there are likely hundreds of calls to the OW in those records. That might be helpful documentation.
I paid the bills for 28 years so everything is tied to me. The phone however is in his name but emails, text messages and the bill came to me. I tried logging in to see if there were calls to one number but since it was in his name I couldn't get it. To nice him back I did change the address so he'd get the bill. I get everything else.
I'm in that place where I want to inflict pain or at the very least irritate him (my IC says this will pass). His bank account got hacked and he lost $1500 (I swear I didn't do it) therefore some of the bills I set up on automatic pay bounced. The phone bill was one of them. Delete, delete, delete. Not my problem. He's also tried to get a replacement cc that is tied to me. No dice. Tried to get some medical bills paid. Nope.
The kids say he's struggling with the budget. He's not good with money so he has no idea that I'm even getting the emails and text messages.