Testing faulty trans/rec shields?

Amongst a large Cyberbrick order that I received recently I have the following:

4 Multi-Function Core Boards
3 Remote Control Receiver Shields
3 Remote Control Transmitter Shields

After a LOT of messing around and having to re-flash 2 of the core boards I now have 1 working transmitter shield and 1 working reciever shield.

The other 2 core boards work if I swap them into the working trans/rec shields.

The other 4 trans/rec shields do not work.

Is there a way of testing these shields?

I have an open ticket with BambuLab but they take an average of two days to reply to anything that I ask. They also keep on asking me for photographs and serial numbers of my faulty printer???

I also have 2 faulty LED’s out of the six supplied in the kit. Not a good percentage.

I have two days left of my 14 day return window and I am in a good mind to give up and send the whole lot back.