Apparently they tried to email it first, but the 15 MB email exceeded my email server's size limit, so they posted a hard copy instead.
I had this when I had to keep asking them for a bill each month and the trick is, is you put them in a position where they'd have to hand you something known as a lock letter, which they will not want to do. as then you can complain to ofgem
So the question to ask them is," what do you have to do in order so that I don't have to ask you again?"
also just bypass ocotpus' support on email and email greg@octopus.energy and you'll be escalated to the top tier support.