Xiaomi India — Unprofessional service at Noida service centre.

I had purchased Redmi 2 Prime 16 GB, white color vide order no Snap deal order no [protected] placed on 7th November 2015. The phone was delivered to me on 11th November 2015. However I did not receive any invoice with the phone. On talking with the snapdeal representative, I was told that a duplicate invoice can be generated from the site. But that feature does not seem to function. I was also told that the order number would suffice for any issue.
the phone was working fine till august 2016, when I noticed that it has gotten too slow and would take ages to start up. When I visited the noida service centre in August, I was told there was the problem of the phone getting too many temp files and cache had to be cleared. the service centre executive sort of cleared it but after a week the problem came back. I continued using the phone . On 7th of November the phone shut down and would not reboot. I visited the service centre on the 9th November at 5.00 pm. But tey refused to accept me on the ground that no more service request can be accepted for the day. I went again on 11th to be told that there is a software issue with my phone and which would cost me rs 300. I told him that the phone was in warranty but I was asked to produce the invoice. I gave him the order number but he would not accept and wanted a hard copy of the invoice. Today again I went to the service centre with a snap shot of the order history of snapdeal as the invoice cant be retrieved. But the service centre was closed today for some maintenance issue.Now my problem is that Iam not in a position to log my complaint even with the service centre for no fault of mine and my warranty as expired. please redress.