As @raohenry said, contacting Square is your only solution. This board is just users helping other users.
As a start, you can verify that you are logged into the correct Square account. you can try logging in on a computer rather than a Square device or your phone just to check other options. This is typically the number one reason people have for missing transactions if they log into an old account or their work/personal account.
The other option is did you have a chargeback and that is why your account seems low.
