Ask an Property Solicitor. Get an Answer ASAP.
You cannot give in a notice and breach the terms of your tenancy based on a faulty microwave. You will then be liable for breach of contract.
Yes if you wish to leave then do it in line with the terms of the tenancy so you are not subject to any claims for breach of contract. Unless it is in the contract itself to provide you with a microwave then unfortunately there isn’t much you can do except buy a new one, or use the alternative method she has suggested. I know this isn’t what you want to hear but her job is just to ensure that she abides by the tenancy agreement. The microwave is not classed as an essential like a shower or bath etc especially if there are other means of cooking food there. Just like a TV wouldn’t be classed as an essential. I am in agreement with you that she is being difficult and should either fix or replace the microwave but legally speaking there is no requirement for her to do so unless it has been stated in a contract. Just do not breach your own contract and open up yourself to a claim based on this. All the best, John.
The call comes up automatically I did not request it so please ignore it and provide a positive rating, thank you in advance. John.