Need advice

I got an email from some person who is interested in buying one of my painting.He wanted to on behalf of a client,but want to pay me by check.Check will be more than my asking price,he wants me to deduct my price honestly and send him back the balance through Western Union.My daughter who works in the bank advised me not to do it as it could be bank fraud, and i could be held responsible for fraud,but I already snet back the email that i would accept.then i sent another emial telling thje buyer that i cannot accept the check but will accept payment by pay pal.Did i do the right thing or I will lose the buyer.