Discount confusion

Good morning,

I recently made my first purchase which was for an amount of R4645-00 at TWT Lynnwood on the 11th of November 2019. As advertised on TWT's website it states that for your first purchase of R1500 or more you get a R500 discount (valid until 31 December 2019) however the TWT Lynnwood store told us that it will be deducted on RCS’s side, however the R500 has not been deducted from the original purchase amount and when I contact RCS they tell me that I should enquire with the store, but as I previously stated the store says the discount must be app**** by RCS. Please could you assist me with to clarify where our discount must come from and sort out the confusion.