Sony — Power Bank charging issue

Address:

38, GM Nagar, Ukkadam, Coimbatore-641001

I bought this power Bank and warrenty period completed. Now I am unable to use becz charging issue and not getting charged through mobile. Even I used rare occasions and usage is very less. I bought this power Bank RS 2500 but Sony authorised service centre saying that warrenty period completed and unable to open this for service. What should I do on this and since it is brand model. Kindly advise. Call me @ [protected]