Lost groceries,no assistance

I ordered groceries using the 60sixty app and to my surprise as I track the driver it says my groceries have been delivered but I did not receive any groceries,don't they call the cellphone number to confirm if they are lost,I'm also disappointed that I sent emails to notify them but there is no response,called all the checkers supermarkets around town with no help and finally when I call the correct store which is checkers savanna mall,I'm told that the 60sixty team with call me back and I have been waiting for a call since,how can I get assistance in this scenario,I am really out of options,please assist