Disgusted by servixe received

KFC Lyell Street Ladysmith KZN. Irritated is just an understatement.I placed an order and needed to use a voucher from my employer ,to pay for this order.Before I could even proceed the staffmember who was next to the cashier that was assisting me,told the cashier to check if the voucher will be accepted by the system,since their system couldn't process a voucher from another company a day before.So yes,my voucher was rejected by the system and then the cashier requested for the transaction to be voided.The lady who came to authorize first said "oh you know people were fired in PMB for voiding of transactions "...and I was lost as to why are customers being impacted negatively since i couldn't proceed with a transaction i had initially made and had to cancel due to their system rejecting my voucher.I then confirmed with a cashier as to what was a reason on their system for my voucher to be rejected she said it has been used...not invalid or some sort. The 3 staff members continued talking amongst themselves that the same issue happened with another customer who had a voucher a day before. I'm still puzzled as to why these staffmembers who keep blaming the vouchers instead of their system for rejecting the vouchers. What irritated me the most is that,the other staffmember went on saying "oh I wonder why (mentioning my employers name) would give their staff invalid vouchers,eish shame that company why are they misleading their staff".The nerve of her...So yesterday when I went to Howick i used the same voucher and it worked with no issues.I'm disgusted by the treatment received in kfc lyell street and ejat irritates me the most being told the voucher was already used.Who in their right mind would embarrass themselves by going to buy food with a used voucher.This clearly implies I'm a ****mer and a chancer.Furthemore,the food I had then ordered again had no salt sachets and this is a norm it's not the first time .Last month I was yold the store was out of salt...what a joke yet this is their biggest store in Ladysmith and how are we expected to each unsalted chips.