Issued a Prepaid MasterCard for Balance Over-payment - How Do I Request a Check Instead?

I cancelled my AT&T/DirecTV service back in April. I paid my last bill shortly thereafter. A month or so later, I received a letter in the mail containing a prepaid MasterCard with the amount of money I had paid for (what I thought was) my final bill. Turns out I double-paid by mistake. 

The letter included a sub-section that states, "We offer more ways to access your payment", followed by:

1. Paper Check (Go online to get your funds via paper check) 
2. Make Purchases (Use the MasterCard)

3. Bank Transfer (Go online to move your finds to your US bank account)

Ideally, I'd have them cut me a check instead of being pigeon-holed with a prepaid MasterCard. I was unable to find anything on my login/profile that indicated this was an option, as the letter states. The letter does not provide a URL. 

Can anyone point me to a URL that will send me directly to a request form (or whatever it may be) that will allow me to submit the request to have my prepaid card cancelled and a check issued, instead. 

For the record, I have not activated the card yet. |

Thanks in advance for any help.