PnP - charged for items not delivered

I have been fighting for over 2 months now to no avail to get a refund of nearly R600, which is the value of food items not delivered which were supposed to be during the first week of the lockdown. I have emailed (never get a proper reply) phoned - I don't know how many times - two in the last week alone. The call staff have 'escalated' the problem, and said a credit would be forthcoming, at least 3 times now. It always comes to nothing, they are impotent. Seems that the store has to do the credit, which so far it has not bothered to do, for whatever reason.