Doesn’t make sense

Mantis owes my fiancee nearly $12,000 and won’t pay him. They won’t even tell him how he can get the money released. They worked with him since 2015 or 2016 but all of a sudden won’t communicate. Having lost a son in April we have both worked less in recent weeks so having $12,000 withheld from us impacts out family and isn’t ok. Mantis make this right!