Hi, the piping under the sink is for a two basin sink with a half flap that also has a vent . The water started filling up both basins but not going down the drain. I cleaning out all the pipes but still not going down drain , the vent in line with pipes is it causing the problem do I NEED A NEW VENT TOP.

Joseph

two basin sink with a half flap that also has a vent

What is half flap? Can you show picture?

the vent in line with pipes is it causing the problem
No.