UHF microphones (City Centre NR1)

Black Prosound make, each has 4 selectable UHF bands. I can't test them. However it seems v. unlikely that the fault is in the microphones, as the receiver doesn't pick up from either of them. I think Prosound is a badge of Maplins where I bought the system. They are no longer trading, and I have tried unsuccessfully to buy a used receiver online, so the mics. are no use to me. Someone could use them if they have the right receiver.