it maybe that they shutdown for few countries
No, both Bitmart and BitMEX are shutting down global operations, this is not related to any specific jurisdiction. After the final closure, these exchanges would be unavailable to anyone worldwide.
If you buy and keep bitcoin on an exchange, you trust them to keep your bitcoin safe and let you withdraw anytime you want to withdraw
But what happens when they shutdown?
If it is an orderly wind-down like in most situation, customers are given a specific period in which they have to withdraw their funds. E.G. in the case of Bitmart, all operations on the exchange will be closed on January 31, 2027, so customers have until then to withdraw their funds. However, it is advisable to withdraw as early as possible in situations like this, for obvious reasons.
I think i should add what cz had to say about Bitmart shutting down:
Changpeng CZ Zhao, founder of Binance, responded: Tough times (again)! At least, it appears to be an orderly wind down where users can withdraw their assets. Pro tip: Self custody if you know how to keep your seedphrase safe (Trust Wallet). Or use the largest exchange (Binance) with staying power.
Typical cz, anyway, do not pay any attention to the part i highlighted. Never store your funds in Trust Wallet, because it is a closed source crap wallet and obviously you should know better than to use Binance as a wallet.
