Hello @Mark_de_wet 

sorry to hear about the experience, here are some other methods to pair the powerline uinit.  

1. Try to pair manually: please  put 2 powerline unit in the wall sockets, in the same room, and pair them again :
Paring Note:  press Pair button only for 1 sec, Power Leds should be flashing on both powerline units in pairing process. ( if the Power Led does not blink, press it for 1 sec again)
When the Powerline Led or House Leds are on, the pairing process is done

FAQ: How to secure (pair) the Powerline Network?
-  Connect main powerline unit to router via Ethernet cable, and put powerline extender in another room 

2. Try to pair using tpPLC Utlity 
Please factory reset your powerline unit by tpPLC Utility one by one:
https://www.tp-link.com/support/faq/1612/   

Refer to this instruction to pair the powerline units/ add an extra powerline unit by Powerline Key: 
https://www.tp-link.com/support/faq/1615/

You could also use tpPLC Utlity to change wifi settings: How to customize wireless settings on tpPLC Utility (new logo)?

 If tpPLC Utlity app does not found powerline extender, try turn off mobile data, and security or VPN apps and see if that helps.