Extended guarantee a *******

I gave my microwave in for repairs with the extended guarantee at the of January 2018 and they said that it will take 2-3 weeks. We are now in April i only received it on the 11/04/2018 without the brown tool that the plate must come on. I phone them but to no avail they said they are going to come back to me but nothing. Why do you pay for extended guarantee as this is happening . I am not happy at all with their service.