UK Tell Ltd

Dear partners,
few days back we have been contacted from one company named UK Tell Ltd. and connected with their sales team.
We offered them UK CC route on prepaid terms, payment they did in PayPal for 100 USD only, 5 days they used our routes, when balance was over - they complained we have charged them extra 15 USD, where our support team shared all their usage day by day to check where the difference they got issue over, but after sharing that data they did not replied anything.
But they raised dispute directly in Paypal for the full amount.
Please be aware of such companies make prepayment and doing disputes, it is very unethical where you lost your money and reputation due to such companies.
100 USD is not a big amount, but reputation is important.
Where if there is any issue with 15 USD difference it can be solved, but such companies don't want to solve the issue they only want to eat money of other companies.