Pay back my money!!!!

I placed an online order last week of which half of the items werent in stock (which is not the complaint) I then went to my wallet to cash out my money its a week later and I am still unable to cash my wallet out. R600 of my grocery money the last money for the month and pick n pay refuses to help me. I complained on facebook and you said I should inbox you and then you dont answer my messages. Yet when I place a grocery order you take my money immediately,. So should I walk into any store and take groceries to the value of R600 due to my credit laying with you that you arent refunding to me. What should I feed my kid???? I want my money this is down right theft and you are ignoring me