Higher rate tax payer - pension tax relief

I wrote to HMRC 2 weeks ago asking to claim higher rate pension relief on my pension contributions for last 4 years as I am a 40% tax payer. The letter I received in response does not make much sense at all. First of all it states that the deadlines for amending tax returns is 5 April 2025 (for 20/21 tx year) and 5 April 2026 (for 21/22 tax yr) and that 'we received these returns after the deadline'. These are obvious errors but it's not clear what was intended to be written. It states I must claim overpayment relief (which is what I was requesting from my original letter). I gave all my details in the letter, so it's not clear what else is required? It is an exceptionally unhelpful response and of course, you can't get through to anyone to ask for clarification. It feels the odds are stacked against me just to claim back what I am entitled. It asks for documentary proof of the tax deducted - do I need to include copies of pension statements? I would have thought HMRC would have access to pension contributions etc as I am a PAYE earner. Please help.

Hi stenta,
We will need to access your record to review this for you.
Unfortunately we cannot access this on this forum you will need to contact HMRC direct: Income Tax: general enquiries.
Thank you.