Asus India — Phone charging very slowly

Address:

Vadodara, Gujarat, 390007

I purchased a zenfone in aug 15, through flipkart. Ever since i have been having problems. Now. Since the last 3 days, my zenfone is taking a long time to charge.In an hour only about 4% charging. I am using the same charger, original, but i keep getting a message saying, please use only the original charger provided.
My phone was purchased last year in august, hence it is still in guarantee period.