A LOT of T-Mobile ID issues as a Home Internet customer

I have been having the same issue since I got the service in January and still haven't gotten it fixed. But it was probably my fault at first cause like you said you don't have a T-Mobile cell phone number, but your router/modem has a phone number, well I didn't realize that at the time, and I put my cell phone number in to link it, and my cell phone number is with consumer cellular, and they don't seem to understand that, and also they ask me for some kind of pin/passcode or something, that we never setup. My home internet account is under my husband's name cause he is over the age of 55 and I am not. And they don't seem to understand even that. But I am able to pay my bill as a guest by putting in my account number. Have you tried putting your account number in when you try paying by guest?