Registering for self-assessment

I've registered for self-assessment because I have to pay my HICBC for the last tax year. I received the following email: "Thank you for your form to register as Self-Employed for National Insurance and Tax purposes. Our verification process requires that your registration form be passed to another department. This department may contact you for further information relating to your application. Once we have completed the verification process your registration will be processed you will receive a letter from us which will confirm your Unique Taxpayer Reference (UTR). Please keep this reference safe." I honestly have no idea what I did to register as self-employed, but maybe I ticked the wrong box somewhere. How do I reverse this? I am PAYE.

Hi,
For assistance please contact the Self Assessment team:
Self Assessment: general enquiries
Thank you