So, if his was fine, why would he buy yours? AS IS means AS IS,,,
That would be my question also. Why did he purchase your transponder when he already had one that was operational? A suggestion might be to get the buyer's phone number and give him a call. Getting a feel of whether he is being sincere or not. At least offering an initial benefit of the doubt. If he is friendly, cooperative, and appears to be honest, maybe work out a compromise? If he is a jerk, well, you just got your answer then of his true intentions.................
