Unfortunately, No :)
Hence, we recommend buying credits only as much you need them and topping up only when you are about to run out of credits. This helps you & us run our respective businesses hassle free.
Plus we'd rather wish to spend our time making Snhyper the best and one of its kind messaging platform in the whole world rather than deal with petty billing issues.
(Probably that's why we offer a limited number of snhype credits to all our users every few weeks totally free of cost!)