Hell and back to insure replacement

I have had a shocking experience & sadly the insurer is the only one I was in contact with to blame. I received the wrong replacement device, upon receiving correct one I phoned in to make sure the policy had been updated which it hadn’t, I gave the imei number to a consultant over the phone, she promised to send me documents, she was very confused. One before her had said the imei and policy needed to be updated, this woman stated I’d need a new policy! She did not send me documents, I am away on holiday and now the phone is malfunctioning as well as not insured? Why is this the customers ****ing problem? This is hell.