Tudortech (Dyson) non-service

Tudortech are the official Dyson repair service. Their service has been shocking. Previously the charging unit for our vacuum was faulty and we waited three months for stock. Now the trigger unit for the vacuum has broken and we've been waiting another 3 months for the replacement. Every time we phone Tudortech they have the same speech that the stock hasn't come in. I have asked five times for a service manager to call me and every time I get the same lame statement that he/she is on a call or in a meeting. I do not believe that a company cannot know what stock is needed and when it is due to arrive. I now spoke to a service advisor and she says that the fault does not lie with them but with Dyson who have not sent the part.