Direct Express complaint: Why won’t they pay my bill?

I just acquired Google Fiber for my Internet provider. My only income is through Social Security retirement. I originally received Social Security Disability from 2014, which was changed to retirement when I became of age to do so in June of last year. I have had a Direct Express card since 2014. My Social Security payment is direct deposited into this account each month, I have had 0 problems with it being an accepted form of payment for any and all …until I got Google Fiber. I have had enough money in my account all month, August 2023, to pay my bill. Direct Express refuses to pay the bill out if my account. They will not pay an automatic bill pay request nor a manual payment request, I have requested by phone that they do so 5 times now, I believe. I now have a delinquent account with Google Fiber. I have had to have someone else pay my bill and will have to draw out cash from my Direct Express acct so they can deposit it back into their account. I am not happy. This is supposed to be accepted anywhere MASTERCARD is accepted. Google Fiber states that this is an accepted form of payment. What is the problem?