Why someone would use your service, pay extra 5% and wait for you to come online and process the topup when they can get them easily from 3-4 bitcoin accepting top up sites instantly
But yeah like irfan_pak10 said, 5% isn't high if you are providing top up for those countries where others can't. But I am preety sure that won't gonna happen from you
By the way bitrefill have more fees for some provider than piiko @mobnepal
I do agree with you in this matter. Most of the providers are cheaper in Bitrefill than piiko but not all
Also, Bitrefill lacks lower amounts sometimes. For example if you saw a $1 minimum option today then you might see $5 tomorrow. That actually happens with me and in that situation I use piiko. Wide number of option to choose and almost same rates