Repeated “no contact” letters

Who do I report data inaccuracy’s to? Long story short I appealed a HICBC, won, now repeatadly get letters saying I haven’t paid or been in contact and blah blah will happen. Each time o get a letter I write and send recorded delivery, and phone and speak to someone, even after holding for two hours. In the mean time HMRC are writing to me saying I’m due a refund

Hi Kevin Wincott,

If your appeal was successful we would not expect you to keep receiving letters advising otherwise.

You will need to contact us again please to update your records:

Self Assessment: general enquiries

Thank you. 

and there lies the issue, ive sent you the letters repeatedly, called and spoke to people but no one does anything. your quite happy to tell me im due a refund but trying to get it is another matter