Seems to me this is going round the houses! I am sure the machine is at fault, you have to assert your rights to a replacement as the item is not fit for purpose. You should not have to put up with that much movements. We have two Hotpoint w/machines and they do dance a bit but not to your level.
The more expensive machines have cast iron weights and the rest concrete.
The more expensive machines have cast iron weights and the rest concrete.