Presume you are talking about an actual 'Hoover' and not using it as a generic name.
I bought a Hoover vacuum cleaner in 1968, and just after the guarantee expired it broke down. I paid a Hoover agent to have it repaired, but shortly afterwards it broke down again. I took it back expecting it to be repaired for free this time, but the Hoover agents told me it was something else that had gone wrong with it and I had to pay up for a repair once more.
I was determined then not to purchase another Hoover product, and for the last 38 years I have stuck to that resolution.
Considering they also make, washing machines, dishwashers, tumble dryers, irons, etc etc they probably lost out by trying to make a fool of me.
Now I expect you will get other ABers saying they wouldn't be without their Hoover appliances, and I respect that, but you can only speak as you find.
I do know that one of their vacuum cleaners tested by Which in the last couple of years, was so bad, not only did it fail to become one of their 'Best Buys', but the magazine actually stated that it was a model to avoid.
Best of luck 'electricblue', hope you get it sorted out to your own satisfaction.
Just one thing, dont e-mail Hoover head office, send a letter by recorded delivery. This way they cannot say they have not received plus it also shows you mean business.
Do a bit of Googling and try to find the name of the managing director and address it to him. He will never read it, but it will get more attention by his underlings than a standard letter would.