Online Prices not valid/ Give Internet Banking login details

I registered for Builders online shopping. I found the item and was trying to purchase the item online. I failed as you can only purchase an item if you give you private banking login details to builders/ their 3rd party or have a credit card or account. I refused to use either as I was collecting from the store in Strubens Valley. I contacted the customer care for after 5 attempts advised I could purchase the item online and collect & pay at the store. I went to the store and the paints manager advise I should go online and purchase there as the stock is "different." I went online found the item and once again had to contact the customer services who insulted me advising that for what they have the store. I then spoke to an online team manager who told me that he is not sure why the item was priced as it was and due to the error I could no longer purchase the item. (This is false advertising and a violation of the customer protection act). He said that I should provide my internet bank login details to complete the sale... :( I went online 2 days later and the item is still available on the site and available and at the reduced price.