My service is 10% fee.
Do you think that people are so stupid to pay you 10% fee for mobile top-ups. If you were offering small fees then some people might be interested to try your top up services but you're offering insane fees and that's why I believe no one would ever avail your services.
Even if you offer low fees then I still doubt that you may not get any orders because of your rank. If I were on your place then I would be using an escrow to offer such services so others might get interested in the service, and I would reduce the fees to as minimum as possible.