Just posting for anyone else who finds this - Same thing happened to me!
I put one in last night for the first time and foolishly thought I didn't need a string - well it slipped passed the point where I could easily remove it this morning. My hubby tried too for an hour and I just got frustrated and sent him off to work.
I kept reading online and realized I should have made him try to hook his finger instead of trying to grab it with two fingers. Then I read where someone mentioned trying orgasms and/or bowel movements. Tried the orgasm but that's not something that's easy for me to do. Luckily, I suddenly had the urge to poo (been a little backed up since I'm pregnant) and sitting on the toilet and doing my business made it pop right out!
So, take a poo. Or maybe even just try to push it out while you sit on the toilet. I think just sitting on the toilet pushed the clove into the canal and out of that space between the cervix and the vaginal walls. Hope this helps anyone who finds it!