Hello,

I need to make a few customizations for now to close my first stage of customizations and apart of that i will need to make next stages of customizations in the nearest future. That is why i want to ask you what a solid developer you recommend for a strict and long cooperation?
YouNet (Time model) - it looks very expensive and it is hard to get a calculation from them before they finish tasks
FoxExpert - the delay in finishing tasks are very often
Foxer
or any other developer?

 it is hard to get a calculation from them before they finish tasks

You're not going to get this from professional developers. Any developer worth their salt is going to charge you per hour, and stick to that.

The reason that devs don't do 'fixed prices' is because people like to add things in at the last minute, and expect them all done for the same price. It's a pretty popular trick.