Woolworths cashier staff very ***********

I'm so disappointed in Woolworths as a company.I have been a customer for so long and the treatment received now after a query is pathetic.I received an sms to say if I buy on my woolies card for R1000.00 on or before 27th November I qualify for a voucher of R300.00.I especially went to woolies on 27th not realising I only have credit to the value of R870.00 as I made a previous purchase of OVER R2k.However I told the *********** cashier the cash difference to qualify for the R1000.00 offer she needs to put it on my woolies card which she never did as she just rang the difference in cash which automatically disqualify me from getting the R300.00 voucher which I specially went on the 27th to qualify for the R300.00.I'm very disappointed as I queried it via your online queries.No investigation was done just a reply to say I did not qualify after I tried to explain myself in a lengthy email.