Unable to pay off phone

I canceled my mobile services in April and since then I’ve been through every round of support, in person, via phone, via video call (in store). I’ve been forwarded all the way to the top of support and no one can remove the current card on my account or update it to the card I need to use to pay off the device. 

I canceled my account and now when I go into the mobile section, it has the balance of the phone. I want to pay off this balance but when I go to make a payment or change the payment method, an error comes up and the system says I cannot make a payment because the account doesn’t exist- this is the page after I’m viewing the phone’s balance. 

I’ve told support I do not want the card on the account to pay for the phone, it simply doesn’t have the funds to pay for the balance. I do however have the funds on a different card and simply want to pay the balance with this card. I’ve also told them to remove the current card on file but they keep charging the monthly payment on it. I have no way to change or update this card and apparently neither does support.

This has been MONTHS of support telling me to call back before the next billing cycle and they’ll be able to help. But every time I call, it’s the same thing- they’re unable to update the card on file. I don’t even authorize charges on the card that’s on there, but they can’t remove it. So they’re charging me on this card against my permission.

I just want to give you my money, why are you making this so hard? Please have someone who has the correct access to update cards on closed accounts to contact me.