What happens when stocks are suspended, and then company closes down?

So the best way is to sell the shares asap before the suspend date ?

If you mean the company files for bankruptcy and delist, then it'll be the same as a normal listed company, which is the shares will have no value and your capital is basically lost.

If the suspended company is taken private and delisted, shareholders will be bought out at a price determined by valuation of the company at this point.