Sales Rep created 2 accounts...

Just to clarify "charged twice" - you all see two charges on your first bill for your new home internet line. The first charge is for the period of time you used from day 1 up to the next billing close date. The second charge will be the full amount for the the next month since TMobile bills forward and not in arrears.

Any refunds that were issued due to cancellation of any services will not show up until the next billing cycle since TMO can't change the current months' charges after billing period has already closed (this is when you receive the paper bill). You just pay the amount shown and your next bill will be adjusted with your refund.

if you did indeed get charged for 2 lines, you will see 2 lines on your bill with two different phone numbers. You need to cancel the other line if this is the case. Just make sure the SIM card matches the number of the one you want to keep. TMO does not charge any phone number for more than one service.

I had a similar experience where I was getting my original TMO gateway replaced with with the newer model. When I received the new gateway I saw there was a second line and phone number that showed up on my online account. I called TMO support directly and was told the previous rep accidentally setup my replacement as a new line. Once the rep cancelled the extra line she told me to go ahead a pay for the extra line since my billing was already closed for the period, but I will get the refund credited on the next bill. The refund on the next bill was exactly the same as the charge for the extra line on the previous bill.