NEW ACCOUNT VOUCHERS IS A ****

I have had a Truworths account since last year June. Witha R500 Credit. When opening my account I received all these vouchers for purchases however have not been able to use most of them because of the credit limit. My account is paid every month via debit order and sometimes I make additional EFT payments. When I called in to ask for a credit limit increase I was just told no sorry it happens automaticaaly but to date nothing yet and I missed out on all the vouchers for opening the account. Having no debt except my truworths account and no credit limit increase and the lack of assistance from Truworths to look at my profile manually I am led to believe the vouchers they offer you when opening your account is a **** to get you to open the account. Why offer you these vouchers if you can not even make use of it and if you pay in the difference to use the voucher they list you on the credit buarea as going over your credit limit and this effects your credfit score negatively