iPhone 1st Generation audio problem

Hey. I have a problem with my 1st generation iPhone. When I try to make a call / play songs the sounds doesn't work. And when I change volume it says: ''ringer (headphones)'' when I'm NOT using headphones. And when I plug in headphones / audio jack duplicator the speaker starts working normally. So actually when the headphones are off, iPhone thinks they are on and when the headphones are actually in, the phone thinks they are off. I tried to restore already, that didn't work. Can somebody please help?

Menge said:

It seems like something got into e headphone jack making it think it's plugged. Try blowing into the headphone jack.

Click to expand...

Didn't work, well I could try taking off the back housing and checking the headphone jack but I don't have the tools.