If you’re using Coin Payments you might not be aware that they sometimes impose minimum amounts for some crypto currencies. Likewise, some exchanges won’t let your customers send less than a certain amount… one some currencies.
This is especially common with Bitcoin and Ethereum, and we often get emails from advertisers complaining they can’t/won’t complete the transaction because of the minimum would double/triple the price for them.
Your best option is to make sure you have other coins enabled on CoinPayments.
In particular, Litecoin seems to be the best option for sending & receiving small payments. It’s also a whole lot faster than the bigger coins, so it could also make it more likely your customer stays on the page until the payment is confirmed… so the transaction is marked as complete in that session.
I’ve also found TRON and DOGE to be good for small amounts… TRON in particular is usually super-fast!