The toilet isnt flushing and water is not filling into the cistern? (at the top) how do i fix this problem??

If I understand correctly, the tank that holds water is not filling up with water.

1) If this is the problem, then you need new toilet fill valve.
Or clean sediment out of existing fill valve by removing and soaking in CLR calcium rust lime.

To replace fill valve:
Look at water supply line coming into tank.
Supply line connects to fill valve.

Buy new fill valve at home center, hardware store, or walmart, or online.
There are two nuts connected to valve. Each nut has companion rubber washer

One nut & washer seal water supply line to tank.
Second nut & washer seal valve to tank.

2) If water tank is full of water, but water does not flow rapidly into bowl when you push flush lever, then your toilet is clogged with sediment.

To solve sediment problem when flush water will not flow rapidly into tank, then buy CLR calcium lime rust.
Pour CLR down into overflow tube located inside water tank.
Make a funnel by cutting off bottom of water bottle, or cut paper cup into a funnel.
Pour cup-full after cup-full of CLR into overflow tube until sediment and CLR are coming out all flush holes located under-rim on bowl.

3) Add a comment for more free help.
Also take advantage of fixya phone service.
For a price, expert speaks with you over phone while you work on timer or any do-it-yourself project.
Fixya is always less expensive than a service call.