Self assessment registration mistake

Hello, I have made a mistake in my self assessment registration. I opened an online shop in March but didn’t start actually making money until May. However, because I put March as start date, I have been sent a letter that I have three months to file tax return for previous tax year, even though no money was made. Tried to call but self assessment helpline is unavailable until September. Is there a way I can get in touch with anyone to rectify that mistake? Thanks

Hi Aicha,

If you contact us using the 'ask HMRC online' link you will be able to speak to our Self Assessment department by webchat and we can review,
Self Assessment: general enquiries.

Thank you