First of all if the machine was operating except for the spin drain there was no problem with the electrical service, and had there been a simple 10 second test could have told the service tech there was a problem.

Quite frankly I don't know why the machine operated correct after you had the plug replaced, but one possibility is that there was/is a problem with the lid lock mechanism and that moving it around temporarily fixed it. Another possibility is the timer. A third is something jammed in the system.

My recommendation is that you call Sears, tell them you paid for a repair visit that did not fix the problem and gave a bad diagnosis and that they need to get out to your house and fix the problem with no additional service cost. My thinking is that the service tech had no idea about the problem and just gave the diagnosis of the electrical outlet to get out of there.

I don't know how Sears will respond, but you did not get the service you paid for and I would pressure Sears to the maximum extent possible to get it right.