D-Mart / Avenue Supermarts — My GST NO NOT RECORDED on my bill even specifically requested

Address:

Mumbai City, Maharashtra, 400080

I have purchased certain items for my office use from D-mart, Mulund West, Mulund Goregaon Link Road on 02nd July 2017 vide Invoice No.34-0086.
As the GST was to be levied, I had requested the Cash counter (No.AP-34) to add my GST no in the bill. She didn't understood so rightly called Supervisor, who said NO such system is there. My complaint is unless D-mart (or any seller) records my GST, how can I get the credit for GST included in the Bill ? Please look into and let me know any declaration required from me or anything need to be dome from my end. Please do the needful, so that there is no loss of customers shopping for business use after GST application.