Hi Bitbunny. You have some excellent questions here that had to be asked.
As with any industry in the world, you typically only hear complaints from clients and rarely hear praise. In other words, someone is far more likely to post that they're having an issue on an exchange rather than saying that everything went perfectly. If you stop by our
Bitcointalk post, you can see that usually what happens is someone has an issue, it's dealt with and resolved. There are always abnormal cases that take longer than others, but those are very few and far between.
If a fiat deposit is found to be fraudulent, it will be returned to the sender. Usually cases are just as simple as that, but of course every situation is unique.
If you need anything or if you see someone that needs help with a Kraken issue, please have them drop by our
Bitcointalk thread.