Delta Dental We will pay for crowns but not your crown Alpharetta Georgia

When I lost a tooth and a couple of years ago I thought that I may want to have it replaced, so I had an implant put in.  I recently decieded to have a crown put in because my teeth were moving.  I was under the under the impression my dental plan states that it pays just under half on a crown.  They had covered my crown before.  After having the crown put in I then received a notice from Delta Dental stating that they will not pay for anything.  When I contacted them they simply stated that since it was a crown on an implant it was not covered.  I then asked if it was a regular crown if they would cover it and they said yes.  But because I had an implant I they don't pay anything.  I asked them if this was fair and they simply said that they do not cover this.  I then asked if there was any recourse I had to try and get them to cover it and they kept telling me that it was not covered.  What a scam.  I had this crown put in under the assumption that they would cover part of it.  They told me that if it was a normal crown they would pay for it but because it was over am implant they would not pay anything.  Now they say that I can't do anything  about it because it is not covered.   Don't sign up for Delta Dental.  They are dental insurance Nazi's.  They don't care about you one bit.