Child benefit higher income charge

Hi there, I’ve been told I need to file a tax return for a year my income was 50600 on my P60 as my income however it does not take into 2k that was paid into my workplace pension AEGON which would then take it under 50k but it does not display on the P60 only my payslips and HR are not helpful as I left over a year ago. I called and spoke to someone in self assessment but he said he was unsure, can someone please help as an agent I spoke to did not seeem impressed that I had not filed that return from 2020 but at the time I was told not to worry and as I was under 50 after deducting the pension I didn’t have to but now it’s seems otherwise? Thank you in advance

Hi
We would need to review you record to check if a Self Assessment is due.
If you contact HMRC at Self Assessment: general enquiries