I have been using mama money for 9 months now everything was ok I even won a prize for the

I have been using mama money for 9 months now everything was ok I even won a prize for the first time in my life but recently since last month sometimes I use my card to pay knowing that I have money in my card but it will decline and say insufficient then the next day I use it again to buy the same thing that it declined yesterday the process goes smoothly which leaves me confused but other than that am happy with mama money