We never do work for Muslims as a rule. It’s just not worth the haggling over price nor the potential of the payment issues.
I managed a small business about 10 years ago. Had a group of Kuwaiti college students who started coming in. Always wanted to haggle over price, and always wanted a discount because of paying with cash. Had to inform them that cash, or whatever, had to report the income and pay taxes on it. They looked incredulous.