I can't see any way out of this situation unless you know someone who could pay the bill on your behalf.
I know you can arrange to pay the IBI bill by direct debit but only if the direct debit is received before they have started to prepare the bills. After the bills have been prepared then it can only be paid in cash at certain banks listed on the reverse of the form.
I believe that someone can go into the suma office and get the bill, I don't think that they have to have authorisation but it wouldn't hurt.
Every year I would receive a suma envelope addressed to the former owner of my property, it was for car tax. After a couple of years I opened up the next one I received and there were no arrears showning so the tax was being paid. The person who now has the car must have been getting the bill from the suma office to pay it.
I also had a similar problem with the car I purchased as it was registered with my plot address instead of my correos. Suma are unable to amend the address but I registered a direct debit for next year and paid the tax at the bank. I brought my car details home with me and have the paid bill to hand.
On the reverse it says EN CAJEROS AUTOMATICOS CAM . Caja Murcia . La Caixa . BBVA . CajaMadrid . Santander. So your bank is one of the banks so if you can't get someone to collect the bill for you what about asking the suma office to send the bill to you.
In an ideal world Suma would send the bill to your Bank/branch and they could pay it but this is Spain and we do things differently here. No disrespect intended but sometimes I just don't understand the totally illogical things that happen. Perhaps that's where the Spanish shrug came from.......others can't understand it either