Urbanpro — No refund of coins even if the enquiries are invalid.

There are students who post their queries, and the tutor contacts them by spending our coins. But many queries are invalid as they post they want online classes but when we contact they say they want offline.
When we report them invalid the company has a cap of 25% on returning the coins.
Why my coins are not refunded when there is either the student's fault or urbanpro fault in due diligence of the enquiries.