F451 Error - Unable to link T-Mobile home internet phone number

I am having exactly the same problem.

Two calls to customer support have been useless.

We repeat the same steps and get the same results, and then I'm asked to hold for a technician. Each time I give up holding after 20 minutes.

I have tried various desktop and mobile Web browsers, have disabled all ad blockers at all levels, and have even tried using three different Internet service providers (my old one, my new T-Mobile home Internet service, and cellular data on my phone).

Note that we should, in theory (I haven’t tried) be able to pay our bill as a guest (an option below the option to log in), but this does not allow us to see the account details, plan, usage, etc., so it is not a solution (even if it actually works and accepts a payment).

It's clear that T-Mobile has lousy computer systems (the series of serious security incidents makes that painfully and publicly obvious), but my experience is that T-Mobile also has no effective customer service. Although we talk with real people in the US, they are as uninformed and unhelpful as contract call center workers overseas, and there is no escalation staff (endless wait on hold until customers give up).

I really regret providing my biographic details, including my Social Security Number, to T-Mobile to sigh up for this service in-store.

Since online account access just doesn’t work for T-Mobile home Internet customers, and there is no help, I’ll just return the device to the store tomorrow.

My main piece of advice is NOT to cancel your existing Internet service. Thank God I did not, and my only losses are my personal data (wish I hadn't trusted T-Mobile with it), my time, and the cost of transportation back to a store (which must be a corporate store; franchises don't handle T-Mobile home Internet).