Poor customer service

I'm so dissapointed at pick n pay cresta I went there the whole week last week looking for oreos special they had no stock they always promised they wjll have stock delivered try again tomorrow in 2 days and so forth but I didn't worry too much today I went there since its the last day of special I requested for rain check and they refused I requested to speak to the manager and he refused as well telling me they can't do rain check for black Friday I have been patient with them and it's not my fault they had no stock when they advertised the special