Fuel vapor canister

In April 2016, I received a recall about the canister purge valve (CPV) possibly malfunctioning on my car. I took it to my local Ford dealer and was told after tested fine. A few days later, my check engine light comes on. I take it back to them and turns out they forgot to reconnect some hose related to my fuel system. They reconnected and all was fine.

My engine light came on again this past March and when I took it in for an oil change, I had them check it. Charged me $100.00 diagnostic. Told me they think I just had debris in my fuel filler neck and they had reset the code. They told me that if it came on again, I would need to replace the fuel filler neck.

Of course, the light comes on within a day. I call back and they order the part. I pay $200.00 for the part and installation. I pick it up on Wednesday and the engine light is back on by Friday.

I call again and they tell me to have it scanned at AutoZone to see if it's the same code. It was. P0455. I bring it back in today and they tell me the fuel vapor canister has fuel in it and is bad. They want $450.00 for the part and another $100.00 to install. I said no way. I can find the part cheaper and I have a mechanic who can do the install. But, they want to charge me another $100.00 diagnostic fee for looking at it again today. I think that is absurd.

My question, is it possible that they not reconnecting a hose on the original recall caused the fuel to get into the canister? I never had any issues with my fuel tank until they did the recall work.