What parts are missing from this circuit ?

Judging by the condition of the pads some components haven't been fitted for whatever reason. On the right photograph there is evidence of two SMT transistors having been removed (excess new solder on the pads). Quite what value these transistors would be and if they are the problem would be guesswork. I can only suggest you get a couple of general purpose SMT NPN medium power transistors and try them. Maybe you can try trawling the net for a schematic. Personally I'd go back to the store and take the refund.