I receive GIP and ESA. HMRC demanding 6k!!

Hello as above. I've been in receipt of GIP 75% of my salary less any ESA I may claim since 2019 (as is the wording on letter from employer). This is paid to employer by Canada Life. Employer pays me after deducting tax etc

I started getting ESA contribution based in 2021.

Ive received tax demand from HMRC stating I owe almost 6k for years 2019...2022..2024...2024...2025

Phoned HMRC who told me DWP are using same code as employer. They advised I contact DWP to see if they will meet the tax demand half way.

Not phoned DWP yet. Well... not got through yet. Thought I'd do some research here.

Has anybody been In this position recently please?

The GIP is only payable until I'm 65 or dead sooner! LOL. It is not part of salary sacrifice.

I've got secondary progressive multiple sclerosis... I will not improve... slowly degenerating… still officially employed.

Thank you for any advice .