How to make sure the user receives lightning payment?

I am working on a side project to allow users to receive some payments from it. When a user clicks a button to withdraw to a lightning address, my webapp makes a request to the host of that lightning address and makes a payment.

I can see the transaction has finished and everything is fine.

But I face situations when people say they didn't receive anything even though the logs show that it should have been received and all settled.

I know it can be some shady users actually receiving funds but claiming they didn't to try to get more from me. On the other hand, it can be that users have some technical issues or lack of experience using lightning and they really didn't receive anything.

So, I cannot say with confidence when it's a case with fraud and when it's really some issues on their side.

Is there a way to protect and to know if users try to cheat on me or if they need help?

I can see the transaction has finished and everything is fine.

Then everything is fine, the user has received the payment. Once the lightning channel is updated the sats have been "moved" and that's that. They are probably looking at the wrong part of their lightning wallet or something (for example, looking and seeing no new BTC transactions on-chain not realizing their lightning channel's distribution of funds has changed).