Yes you are eligible for input credit.
Just, remember under GST you can take input of every expense incurred to run your business. (Except few such as food expenses, membership etc.)
You need to provide your GST number to PAYU they will upload in their GST return and you will get credit.
Not only PAYU even banks, Amazon etc. are asking for GST number.
If you have not given GST number then you will not get automated credit.