System Pavers coming apart

Less than 2 years ago, I had System Pavers put down pavers for parking on.  It looked great to begin with but now is coming apart.  I thought that the inside edge was going to be set in concrete but was not.  I was told that if a paver came loose to hit them with a rubber mallet which did not work.  Now I need to contact them and see what the remedy is & hopefully it is not dig up & reset pavers.  That is why I hired them I did not want to dig.