Idea Cellular — regarding 4g network

Address:

Nashik, Maharashtra, 422005

I am using 4G handset Iphone 5. Then also I am getting 3G network any where in Nasik city on my sim which is very slow.I did complaint 2-3 times but no result. Also I am having trouble for calling, I get call failed problem many times even in city area. Please help me or else I will have to port my number.
Thank you