To be honest I would never use your exchange the fees are ridiculous, why would anyone pay $500 more for one Bitcoin if they can buy it also on another website with good reputation. Your website also shows a Btc price that does not even come close to the real price.
Your price: 6774$
Real price: 6265$
We don`t know any website where you can buy btc with real market price, Do you? Don`t forget for credit card fees, site maintenance cost, salary and profit. Why somebody should sell you btc for real price? where is profit?
It's impossible to sell for real market prices since you want to run a business, but a good rating that is good for you and the customer is the best if you want to succeed with your cryptocurrency exchange website. You are using
https://www.liqpay.ua/ as payment provider that is calculating 2,75% fee for each transaction, other popular services who are offering exactly the same are using Simplex that is calculating 5% fee. This should give you some advantage to compete with established websites that have been around for several years.