Topped off gas tank--Won't start 4 days.

[Panchoz3]

Topped off gas tank--Won't start 4 days.
Engine stumbled and died about a mile from gas station.
Got car towed to house. Has been in garage 4 days
with gas cap off, hoping for some sort of evaporation.
Still won't start--4 days.

Tried to siphon gas out. No go.
Seems to be something in fill pipe blocking siphon hose.

What to do ?
How to repair --get car started?

Thanks