Amount owe reflects more than expected to pay

Hi All, I have completed FY 2022-23 IT return. While completing it, it was showing amount to pay was GBP 5.24. However after submitting the self assessment, it was showing as GBP 541 approx. After dig down more, I was able to know that HMRC charged two different amount on 22nd Jan 2024. Amount charged of GBP 250 approx for 2018-19 and 2019-20 each year plus interest since 2018 & 2019. I couldn't able to get more detail than this. Tried HMRC number as well but call getting disconnected. Do I need to pay this amount without knowing for what they have charged and then ask for explanation? If yes, then how I can raise these queries please ? TIA

Hi,
You should have received paperwork regarding the earlier tax years balancing payment due.
If not you will need to contact HMRC to review:
Self Assessment: general enquiries
We would advise to pay the outstanding balance to limit the interest charged and once reviewed if amendment needed this can be updated. 
Thankyou.

Thanks for your reply. Yes, I have done that. I have paid all outstanding amount of GBP 552 on 30th Jan 2024 as per charges implemented dated 22nd Jan 2024 including interest since 2018 and 2019. On 2nd Feb 2024. I got two HMRC letters dated 25th Jan 2024 stating that I have paid excess amount for 2018-19 and 2019-20. These excess amount is in total of GBP 850 plus. On online, it is saying I have to pay 552 for 2018-19 and 2019-20 where as letters says that I have paid excess of 850 approx for same duration. Please note I have made payment after this letter printed. This is so annoying and didn't understand why there is so much discrepancies are.