Seychelles and Belize - just stop paying a renewal fees.
Cyprus? This is something else. Cyprus will not strike off your company just for not paying a fees. There are some legal obligations which you have to fulfill. It is not just about filling one paper ase Admin wrote, here. Cyprus is very strict about all formalities. If you will just stop paying and stop answering, the best case is just to be blacklisted in Cyprus and maybe in all EU for the business for a next 10 years. The worst scenario is, that not fulfilling a formal obligations is a criminal offence. And cyprus︀ authorities can issue arrest warant after some time. But to be honest, I never seen︁ such case. They usualy just blacklist you. And all EU countries has a common blacklist.︂ If you will want to incorporate a company in any EU country in a next︃ 10 years, it will be not possible. And you will be not able to travel︄ to the Cyprus for next 10 years.
Usual costs of closing a structure: Belize and︅ Seychelles - less than 1000 USD each.
Cyprus - 5000-8000 Eur. Depends on many factors.︆
It can not cost more than 10K in total.