Send the check to me. I'll check it for authenticity. Also, make sure your sign your name on back for the check so I can verify your signature.
Don't cash the check before verifying it with the issuer.
Ask for a written explanation and verification of the amount.
When you have written verification, it's money in the bank.
Later on, if it turns out that the company audits and finds the mistake, that's their problem since you have written verification from them.
Worst consequence would be that the company withhold future payouts to recoup their mistake, or ban your form their network.