Why do my credits available for booking become negative when I skip a ride?

Skeddy app DOES NOT book your credits for time-overlapping rides. 
For example, if we sequentially found three rides for 1, 1, and 4 credits accordingly, but the third found one is overlapping the second found one, then only 2 credits will be booked: for the first two found rides which are not overlapping each other.
However, if you skip the second ride, then the third one will not overlap any other ride anymore, so the booked credits will change to 5, and you may face overbooking.

We recommend always keeping at least twice the credits over the booked ones.