My ex-husband has not paid child maintenance for 4 months — what enforcement options?

Yes. File an execution petition (طلب تنفيذ) at the Sharjah Family Execution Court attaching the divorce decree and the unpaid invoices. The court issues a salary attachment order served on his employer's HR — they must withhold the monthly amount plus arrears directly from his salary. If he changes employers, the order travels via the central labour registry. Travel ban is also available for arrears exceeding three months under Article 322 of the Civil Procedure Law.