Credit Card Swipe in Current Account

Dear Sir,
I am registered in gst. I have a credit card swipe machine on my retail outlet which is linked to my current account of the firm registered in gst. I swiped credit card of an individual on my machine for 1 lac rupees. And returned the same amount within 30 days to the same person through my account to his credit card or his saving bank account. Would this transaction fall under sale ? Will i have to pay gst or income tax on this entry ? Please clarify.
And what's the effect it has on that individual who was the card owner ?
Is there any limit of these type of transactions w.r.t time or money ?