Hey Filip
I am sorry to hear about your losses

Do you have any idea of why they passed? Sounds like you said you checked all your water parameters, so maybe the fish were sick. Did the fish look "normal"?
Do you have any pics of them before of after they passed?
Don't get discouraged. The hardest part, at first, of trying to breeding clownfish is waiting for your fish to actually lay eggs. I can be frustrating some times, so that's why it's important to start with quality fish that are already breeding or close to breeding age. We like to see results from all the preparation we are doing for the clowns and its frustrating when nothing but bad things happen.
My advice to start would be to get just get 1 breeding pair of clownfish and keep them in a controlled environment with pristine water parameters. You should be able to find a regular occ or Perc breeding pair for $200-$250. Feed them well and often and they should start laying eggs in a short time. You can get a lot of practice with them and then if you see that you enjoy it you can expand and get more pairs. Remember just 1 reliable breeding pair should lay a nest every 10-14 days so that's 2 nest a month if you collect them all. You will need a new separate 10g tank fry tank for every nest you collect. Over the course of 6mths you could have twelve 10g tanks going before your first batch of clowns would be ready for a new home.
A lot of people don't have the space for that so just imagine if you have 3 or 4 active breeding pairs. You would need a warehouse over the course of 1 year.
So, please don't give up. Just regroup, take it slow, and I am sure you will get recharged enjoy the experience. Please let me know if you have any questions
Thanks
Brian