A Team Appliance Repair

DO NOT call this service, described my issue when I called to the person who answered the phone....washer still working but it stops at various points in the the cycle however if I open and close the door then washer continues to work, water drains and the cycle finishes.
The technician insisted I needed a new drain pump.....I was puzzled as the pump would work if i opened and closed the door, however I listened.;
He returned a few days later installed the new drain pump assembly left the house without a wash cycle being completed ..... the washer behaved exactly the same way.;.....never worked! Said it takes too long to wait to check!
HOW CAN YOU BE SURE IT IS FIXED?
The technician retuned and then told me I told him I manually drained the washer when he first visited! I DID NOT.......and now I need a new control board.
He specifically told me on the first visit that is was not the control board......I have a background in physics and questioned the fact that it could pump would drain when I opened and closed the door.......He reassured me it was not the control board
Thought I had a company that stands by its work!
I have the old drain pump assembly but they will not return to take out their new one and put my old one back to confirm it was in fact the control board from the start.
They will however return to install a new control board.
ARE YOU KIDDING, I was taken for 797.00 dollars!