Poor Customer Service

I have a Samsung Galaxy S5 on a contract with MTN. The contract was originally taken out with Nashua Mobile, but was transferred to MTN after Nashua ceased their cellular operations.<br> <br> The handset was dropped this weekend and the screen was cracked. I took the handset to the MTN store in Canal Walk to claim on the insurance, which was taken out with the contract. I was advised not to claim as screen replacement is a free service. Unfortunately, as my contract was originally with Nashua, the IMEI number is not registered with MTN, so they won't do the replacement.<br> <br> I was told I needed to contact Nashua to get proof of purchase and then take the handset to Samsung,<br> <br> This is not acceptable. The only contact number I have for Nashua is no longer in service, but I shouldn't have to contact them in any case