Best way to cancel service

I am making the switch from T-Mo to Simple Mobile. I have ordered my Simple SIM. I am off contract with T-Mo, $59 EM+ plan, and my current billing cycle ends on Saturday Nov. 12th. What is the most reliable way to cancel my T-Mo account, the website or calling Customer Care?

I hate to say it, but I really don't trust any phone CSR for any company anymore. They pretty much can say anything they want and you have no proof of the conversation. Does anyone have any advice? Thanks.

When you port your number over to Simple Mobile, your account will get canceled automatically.

Thanks for the reply, but I am not porting my T-mo number over to simple. My current number is less than 6 months old and no one uses it to call me directly. I ported my previous T-mo number over to Google Voice and everyone still calls that number.

Then just call in and cancel it.  You can make sure it's done because the phone won't be working and you can also check the status on line.  There's little risk in doing it that way.