Crown was not lasting for one year

Hello,

I had a root canal on the top of that core is build up, and crown was made in 2009, which was there for one year and came off in 2010, in the 2010 the same docotor redid the crown again in 2011 it came off , In the last one week it was smelling really bad after one week when i'm brishing it came off, I went to the same doctor, he with out even properly cleaing resubmitted the whole thing(old crown along with the core), is that is the proper way of doing, for lat one week it was giving foul odour, basically it was not properly filtted, unfortunatly i paid him lot of money evn though he is poor in work i have to go to him.now that shredded crown along with the core is resubmitted that is making me nervous how bad it is going to affect me as that tooth already has root canal, any response is really appreciated