No one at Delonghi will

Question

No one at Delonghi will help, nor will Argos where product was bought. I just want to know if my microwave is safe (bought in May 2006) - the inside of the door (looks like a plastic covering) is bubbling up. I want to know if this is classified as a damaged door or not. I had the same problem with another microwave oven, different model. Please advise as no one else seems to know! Thanks