Money transfer business

Dear Sir

If your client is working as commission agent than you have to consider only commission amount as Income. 

I am a Domestic Money Transfer Agent. My Gross Receipts (commission amount received from customers) are below 20 lakhs only. But I registered myself with GST under the impression that I can show NIL return because the commission (turn over) is less than 20 lacs only. Should I still pay GST @ 18% to Government or Not? I am not charging anything extra from my customers as GST seperately. If I start charging 18% GST, I will lose my business bcoz the next shop guy who is not registered with GST is not charging this 18%. So customers don't come to me. Please give me an idea on how to deal with it!