Toilet not flushing as it did.

[spinnerc41]

We have a 1980's toilet and it normaly works by:
1.When flushed the deposit in the bowl is sucked out
2. the bowl fills up again with clean water.

This is not happening now, when flushed the water fills the toilet bowl then emptys and refils.

What can I do?

Is it a profesional plumber callout?

 

[Softus]

Good afternoon. Is your toilet pan a conventional washdown type, or a macerator?

 

[spinnerc41]

Its a conventional washdown type toilet

 

[oz-plumber]

You have a blockage somewhere.
Time to call someone who has equipment to locate and clear the blockage.

They don't get better - just increasingly worse the longer they are left