@Internetdumbo 

Hello,

Please confirm again some details and we will try to figure it out:

1. What's the light status on the WPA4220 KIT, especially the powerline LED? Generally, the powerline device can extend your existing network via the power circuit when paired successfully, which will give you a stronger signal.

2. If there is no improvement, please press and hold the pair button for more than 6 seconds to reset the powerline adapter to factory defaults. Then repair them with the below instruction and give it a go.
https://www.tp-link.com/us/faq-258.html

After that, please connect your computer to the extender and check the IP address, default gateway, and DNS.
Note: How to get it: https://www.tp-link.com/us/faq-838.html (Please show us a screenshot of the status - details page)

3. If it is ok, try to give the extender a different wireless name in order to confirm its signal:

How to customize wireless settings on tpPLC Utility

Have a great day.