How about blocking the source IP range from all .NG domains to stop the thieving con merchants.
www.maxmind.com provides a free database of ip addresses to country.It has about 256 entries for Nigeria..
I know it will not stop them all but it’s a start…
I have about 3 a day, putting on bids £100’s higher that the value of the items…
Or sending messages like ….
Hello seller
My name is ‘scamming Nigerian’ , I am here in UK / USA etc .
I want to buy your item for 10 times its value.
This will be for my son/ daughter / friend etc & I want is sent to Nigeria.
I will pay you by Western union fake bid pay or my friend; who is a doctor will send you a (stolen / fake) ‘check’ for £3000.
Etc etc etc….