Ok - good - I hope it was clear that I wasn't trying to imply that you are DOING it. You haven't said enough for me to interpret your situation that way.

Generic examples (of how it's happened to me) are:
"I can tell... (insert assumption here. example: "...that you're pushing me away", "...that you're lying", etc)"
"Why don't you just go ahead and break up with me, since it's obvious that's what you're trying to do"
"that's not how you REALLY feel"
"you don't give a cr@p about me anyway"

etc.

I realize it's a matter of euphamisms, and maybe this is just my personal sore spot, but nothing pushes me away faster than someone telling ME how I feel, or people who lay a guilt trip on me for not feeling more than I do. My dad does this constantly, out of insecurity. It drives me batty. I also had two ex-boyfriends that got very negative when I asked for space, and the negativity made me even more sure that I was doing the right thing by distancing myself from them.

To turn it around and suggest what TO do instead of what NOT to do:

- say "it seems like you feel" instead of "you feel"
- only suggest an interpretation or assumption once. If the person denies it, then don't push. You can make up your mind that they are lying, or choose to believe them, but either way, the conversation won't get any better if you accuse them of lying
- be honest and open about your efforts to change, if you intend to do so
- communicate trust, or at least, desire to trust
- do not push

Myzen is right, though, that if your girlfriend has really cut off contact, that pushing the issue is a very bad idea.
Always, if one person pulls, then the other person pushing just makes it worse. If you love somebody, set them free, blah blah blah...