Presumably, you already have a contract with the singer that spells out the payment terms. I doubt that it says anything about the propriety of using a debit card. I think you should secure the agreement of the singer or the singer's agent to being paid this way before you go ahead and do it. And, if they agree, you need to get their agreement documented. Keep the document with your contract papers, in case there is some dispute. If they don't agree, you should pay them in accordance with the contract, or seek local legal advice if you want to push ahead with the debit card anyway.
Yes, if she agrees. If not, then no. Good luck!
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