can't update payment method

I went to the page and entered a new routing # and bank member #, both of which had changed because my credit union and another had merged, but when I tried to submit, the message reads "we are unable to process your payment. Please contact [Edited: Personal Information] for assistance or try another payment method".  I called but it seems like must be a wrong number to some company with a name that sound like "forte", and all their voice prompts were unrelated to what I'm trying to accomplish. Plus, I wasn't exactly trying to have a "payment processed". If this isn't sorted out, my autopay to you is going to no longer work with the old numbers. And with Comcast unfortunately being the kind of company it is, there is no such thing as actually being able to talk to a human anymore. Even one offshore with accented English.