Sixty60 Checkers Reduces your Credit Card limit

Sixty60 pre-authorise any orders and ties up all the pre-authorisations for a month. When they are done picking your order, they do another transaction. For this second transaction they then do not use the authorization they received. The authorisation stays active and accumulates for over a month and this reduces your spending limit on your card by the total accumulated pre-authorisations. I have thousands of rands that went off my credit card's spending limit and the bank requiers a letter from Checkers to remove the pre-authorisations. I phoned Sixty60 and spoke to Lindsey Zoutman. She insisted that I give her the order numbers for the past month. Then she promised to send the letters to release the pre-authorisations, once I email her a screen shot of my bank account showing the pre-authorisations. I sent the screenshot and then Lindsey sent me an email saying that I have to wait for my credit card statement and then email a pdf of the statement to her. So basically you can not get rid of the accumulated pre-autorisations. I find it totally unacceptable that Checkers' Sixty60 can reduce my credit card spend this way and for no reason what-so-ever. They have their money and do not care about the customer. Why will anyone continue to use them?