Offset is being sued by a stylist accusing the rapper of not paying for thousands of dollars of stuff ... and the lawsuit came just days before Cardi B gave birth to their daughter Kulture.

According to court documents obtained by The Blast, The Meyhem Group — which is a Miami-based "personal stylist/shopper" — filed suit on June 28 in Georgia court against Kiara Cephus (aka Offset from Migos).

The company claims they gave Offset goods worth $11,699.60 and says the rapper "acknowledges he owes but still has refused to pay." They claim they even showed him the receipts but still nothing.

Meyhem wants the $11,669.60 (plus $1,500 in interest) for a grand total of $13,169.60.

The lawsuit came just days before Cardi B gave birth on July 11 to their daughter, Kulture Kiari Cephus.