I have issues with my IMEI number.

You must prove that the item for which you are claiming is owned by you and the date of its purchase. If there is a good reason why you cannot provide the IMEI number of your item and the purchase date then you will need to discuss it with the claims handler who will tell you what may act as sufficient proof. You should however be aware that if the ownership and date of purchase cannot be reasonably proven then the insurer may have the right to decline the claim. It is best to resolve proof of purchase before the need to claim arises.