I came up with a fix to eliminate the IPN payment notice delay or loss problem from PayPal.
I wanted to put this out here and have it on record so it can be thought about. I was told it will not be done. I hope others would see this as valuable and easy to fix and you may consider the change.
If we see that PayPal (or whatever other payment system also has this problem if any) received a payment but they did not send you the IPN (instant payment notification) then we could manually process the purchase ourselves.
This could be done on your site using the THank You Email option, if that was changed to accurately reflect a true paying transaction.
Also, we would need to simply add the unique payment transaction ID from PayPal in a list box somehwere so you do not process the transaction again. This part would be simple to implement I believe, even if you couldn't create a feature where we send out a correct Thank You Email transaction.
This would solve your PayPal problems which show up in a long list of posts and even has its own webpage on your site showing problems. You would be another step above the competition with this improvment and we could manage our business better.
We sure know PayPal wont change. I hope you will help us with this.