Sealed plugs

I bought a jet wash from B&Q just under half a year ago, it stopped working randomly, so I assumed it was just a change of plug that was needed as one of the pins had bent, I changed it, still nothing, tried another appliance in the plug, that worked, so decided to take it back to B&Q - here they refused to do anything as I had changed the plug (which ironically I got from B&Q)

Is there absolutely anyway I can get this sealed plug back on that I have chopped off, or can I buy them to try and install myself?

I spotted this post a few weeks ago, and asked the sparky I had at home today, out of curiosity and to help!

Apparently you can buy them, but they are really only available from trade shops, electricians etc and usually are very difficult to wire up, inside the sealed unit you are doing.

Did anyone ever get to the bottom of this, as I have a similar plug issue I need to use now