Raru Accounts logic?

So i got a reply from Raru.

i had R151 credit. i made of purchase of R136 , that should have left me with R15.

their system however made amistake of putting it to -R15

after 3 emails and a call. they still cant get the calculation right. there by i loose R15

might be a small amount but it could have been a large amount.

be careful they don't rob you too