dental post broken

hello my two top  middle teeth have posts with crowns fitted a few weeks ago one of the crowns came loose to reveal the post broken inside the tooth i went to the dentist and after only a few minutes she said it couldnt be removed is there anything that can be done to  remove the post? ,the crown and post were in for about 7 years.she advised a bridge or an implant i dont really want a bridge as my next two teeth next to the two top ones are bridged and implants are very expensive.she cemented the post back in but because the size of the post on the crown is very small it came loose again after only a week or so it came out again.

many thanks jim