What course of action do i take to restore in app purchases that were lost ?

I recently bought the game Dead Trigger, I made a few in app purchases. played until my phone battery died. charged my phone, restarted the game and found all game progress was lost as well as all my IAP's. I dont mind the loss of game progress so much, but losing the IAP's is what makes me mad. Its like i just threw my money away. I reported the problem to the game manufacturer, still havent heard anything from them. If i check my purchase history for my Itunes account it shows the IAP's. what would be my next coures of action to restore my IAP's? thanks in advance guys