Changing the Standard

Good Day

I have been working as a freelancer for nearly 5 years now, and it's been really tough. I usually get the common problems of a freelancer, late or slow pays, and underbudget projects. Sure it was tolerable when I started out, but recently the priority company I been working, started using unethical business practics (as so I see). Late payments, breaching intial agreements and underbudgeting projects that has major labor work( I am not sure underbudgeting is unethical but I like to solve the problem)

When I started with them, everything was okay, projects was budgeted properly, I get paid really well and payemnt was right on time. just recently, the pass few projects I work with them. It seems that the company has become comfortable to the fact that I prioritize with them, and think they can do what they want with me.

I was thinking of giving written contracts to ensure my safety when working with companies I work as freelance and setting up hourly rates to ensure no under budgeting works. Now here is the problem, giving out contracts and using hourly rates are not the standard business practices for my country. When a freelance gets a job, majority of us use blackbox pricing and agree on to do a project based on initial agreement and a handshake. I haven't known a single freelance uses these type of practices. Maybe for directors, dops and supplier. But far as I know editors, graphics artist creative talents that are not with studio employment, don use contracts or hourly rate.

I been looking for change these pass few years, and so far these are only ideas that I could only think of. Are there any sugguestions for my current situation? Is it a bad idea do this?

Thank you for load of help and I hope for hearing for it soon.