When I did initially purchase my Apple Watch (LTE), I used Verizon as my carrier. Later, I switched the phone and the watch to T-Mobile. Turns out that Verizon still charged me for the Watch ($73.18/month!!!). You need to cancel the account and just switching to another carrier doesn't stop billing.
They explained the $73 due to the $10 fee for the watch + unlimited data plan.
They explained the $73 due to the $10 fee for the watch + unlimited data plan.