Merkado online store

Good day

I placed and order with Merkado online shop on the 27/5/2018, until today this order has not been delivered!, a month back i requested a refund as the order is not going to be processed. I have now sent for reminders to Merkado to credit my account and send proof of payment. Until now this has not been done! Is there an online store watchdog that I can report them to ?