Hi Ying Wai Chan,
We are sorry for any frustration you are experiencing in resolving this issue.
Merging multiple records can take time, as we need to ensure that the details that remain on your merged record are correct across all years of the multiple records being active.
If any tax is due following the submission of your paper return, we will write to you confirming the amount, and you can appeal any penalties that arise through not being able to file your return online.
If you would like to contact us, and would prefer an alternative to phoning, you can contact us by webchat here:
Self Assessment: general enquiries
Click 'ask hmrc online'.
Thank you.