Usher -- Held in Contempt for Canceling Ex's Saks Card

Usher just got bitch-slapped in court -- a judge has ordered him to REOPEN his ex-wife's Saks Fifth Avenue credit card in his name ... after the singer closed the account last year.

The closed Saks card was just one of Tameka Raymond's many grievances in her ongoing custody fight against Usher -- and now, the court has taken her side ... holding the singer in contempt for pulling the plug on her fancy charge account.

Tameka claims she needs the account to do her job as a stylist.

As for the other grievances -- Tameka said Usher owed her cash for the nanny bill ... and continually failed to keep her in the loop about where and when he traveled with the kids.

The court agreed ... and awarded Tameka $1,300 for the nanny.