I am surprised nobody has yet to bring up the fact that now you have your credit card number associated with another customers DISH Network account.
Read your contract. In the event of a cancellation fee, or charges for un-retuned equipment, DISH will charge any payment method ever used to make a payment on an account. This means that if the customers account which you made the $50 payment on breaks their contract, or doesn't return their equipment, they could charge your credit card if they can't collect from any other payment methods that other customer has on file.
You might have gotten a refund, but I would consider escalating this to the presidents office to make sure your banking info is removed from the other account.
Granted you can always dispute the charges with your bank, but better safe than waking up one morning seeing you have no money in your bank account.