2001 Honda Odyssey Oil leak

I had my oil changed and after 380 miles I developed an oil leak between the engine and trans. (there was no oil leaks before at oil change) I know that if a seal goes it will start to drip a drop or 2 this leak is about 6-8"circle of oil on the garage floor' I checked the oil and found it was over about a 1/2 qt. I don't know how much I lost in the 380 miles, can you tell me if by over filling could my problem? Do I have any recourse? Thank Rickey