Unknown VAT Receipt

Hello, My client has received funds stating they are from HMRC VAT on 09/01/2024 £703.97. My client reports there is nothing for this value in their business tax account. My client pays and receives all VAT transactions with HMRC automatically. My client hasn't received any letters. My client reports one of their relatives received a similar sum in their bank account without any corresponding details. Is this a repayment for something that I can trace please? And if yes, how do I do this?

Hi Unknown VAT Receipt,
Please contact our Helpline on 03002003700 so that we can open up your clients record and identify why this repayment has been made.
Thank you.