Onlyfans

So I’m a little confused. I took a break from only fans for a long time and didn’t think I made enough to include it in my takes. So I filed my taxes anyways and they got accepted and approved the same day February 9th 2022. A couple weeks after I did my taxes I got a letter in the mail from onlyfans and I made a little over $700. Fast forward to today I have not gotten my federa return yet as of April 4th 2022. I got a letter in the mail from the irs today saying they are holding my return until they can verify the accuracy of my return due to either income, income tax withholding, tax credits or business income. Could this be due to the fact that my onlyfans money wasn’t included? Will I need to amend this? The letter states once they finish their review they will either send me my refund, ask for more info, send part of or none of my refund at all.