SIM Card Billing Error

My iPhone 7 was stolen, I reported it stolen and had the phone suspended. The next day, I bought an iPhone 8 Plus.

However, when we looked at the detailed billing (long story - but we had to subpoena the phone records), the detailed billing shows that the NEW SIM card from the new phone that was purchased the day AFTER my phone was stolen, was used in my old phone the night it was stolen. Obviously, this is impossible because I didn't even purchase that SIM card (with the phone) until the day after the phone was stolen.

To make it even weirder, the OLD SIM card from the stolen phone is showing up on billing records for two days as being used in my NEW phone. Which is impossible! What is even weirder, is that the records show the new SIM card and the old SIM card are being switched back and forth in the new phone in 3 second and 10 second increments -- again, impossible!

Has anyone had this happen? What could cause it?