We have had the same issue, looks like it's a hard one for Schoolcomms to resolve.
Received a generic email on Wednesday: "Our developers are working with our Cashless Caterer partners to resolve this. It is imperative, whilst the fixes are being worked on, and subsequently rolled out, that no manual adjustments are completed via Schoolcomms or your Cashless Caterer provider’s system."
We have a student with £28K balance, a few of the students are planning on putting their money together and offering to buy the canteen.