Hmmm...I seem to remember a thread on something similar with someone traveling LAX-MIA-LHR and only getting as far as MIA due to misconnects and then wanting to know whether he would receive credit or not. Try and do a search to find that thread.

For your question however, I dont know if you could get credit back. Either way, you will have to talk to AAdvantage Customer Relations, and not the EXP desk. Good luck and please do report back.