Flipping SERAFE

I've just had a bill, with the wrong postal address, but in our names, for 730- for 2019 & 2020.

I already paid 2 bills in Feb & Nov 2019..... unfortunately didn't keep bills but have eBanking proof of payment. Basically getting double billed.

I think there is an address issue.... when signing up for phone/internet etc, the phone companies have our phone line under a different address to our actual postal address.

I have a feeling this is gonna be a nightmare to sort out ... not paying it but don't want to get a Betreibung either