Isn't it a good sign for you and for your platform? Because as long as users increase, you will face more difficulties supporting them. It's normal when more users come on your platform; they will make some mistakes as well, and your team will have to solve these issues. That means you have to expand your support team, because you are earning more revenue, lol.
Honestly, sending to the wrong chain is entirely the user's fault. Given that they have met and resolved such cases several times, this encourages everyone who makes a mistake to try for a refund, even if the amounts are very small.
First of all, they would have to add a clearer warning when entering the address, for the user to double check his deposit address. A warning in the order page is also desirable, I haven't seen it.
Earlier, I saw that some similar services offered something like that, but they charged for it. Which often did not make sense for smaller amounts, but at least it relieved support with such requests.