I take occasional payment from my customers using bKash (a mobile financial service provider in Bangladesh). I'm using their personal account option, which is mainly for personal transaction. I load money (called cash in), do mobile topup, make online payment and send money to other bKash users. All of the services are free of cost, except send money.
When I need cash, I do cash out from their agents and the fee costs nearly 2% of the amount cashed.
So, when I accept payment from my customers in this personal account, I ask for 2% extra, since cash out incurs a 2% cost on me. But if I make online payment/mobile top-up with the amount received from my customers, that 2% becomes my gain.
From an Islamic view point, will this extra 2% be considered as interest (Riba) on my part?
Note: I had to completely rewrite the questions to clear many confusions.