HMRC put me on Self-assessment despite being PAYE - now I have penalties?!

Moondreamer

I've been in touch with HMRC over the phone again to request all documentation they've ever sent me from 2015 onwards. Was advised to write a further appeal letter requesting all penalties be dismissed and not to specify any year in particular. I've included a timeline of all my addresses, and a timeline of employment including tax codes and asked them to investigate if these have been issued incorrectly. It also turns out from doing my online self-assessment for 2016/17 that they actually owe me for tax I've overpaid so this is by no means over! Thank you for everyone's responses so far - I appreciate it's not clear cut, tax never is. I've never updated HMRC with change of address, as this has usually always been done by my employer, seems that is the same for most ppl. I get that my tax is my responsibility but I can't deal with what I don't have information on! I'll post back soon as and when I get any updates, thanks all