Error F451 - Service Unavailable

We previously had 4 voice lines and 2 home internet lines with T-Mobile. We transferred our 4 voice lines to another carrier and only have the 2 home internet lines left with T-Mobile. Since one of our voice lines was the account login, they closed down our account access. 

We are trying to get account access using the home internet #’s, but keep getting the error code below:
 

Servicio no disponible.

F451 : Uh-oh, it looks like we have our wires crossed. Intenta nuevamente más tarde.

We have had multiple phone conversations with T-Mobile and also multiple chats through FB Messenger. The problem has not yet been resolved and we are still unable to view our account. 

Does anyone have a solution to this? Or if  T-Mobile employee sees this, can you please help? 

We just want access to our accounts online to view transactions and to make payments. 

Gracias