Received Self Assessment Statement - Not able to understand

Hi, I have received a self assessment statement from HMRC recently, stating I have to pay huge penalty from my previous statement, I'm employed to an organization and I don't think I have to pay self assessment as I don't fit with any category mentioned in https://www.gov.uk/check-if-you-need-tax-return I'm not sure if this is a scam, I tried to ring HMRC helpline, but couldn't get connected. I'm worried as I'm unable to understand the letter and not able to get enough help on this, any advise on this would be highly appreciated. Thanks in advance. Regards, Vinoth

Hi,

We would need to access your record to review. You can contact our Self Assessment team below.

Self Assessment: general enquiries

Thank you.