The sellers (third to fifth appellants, represented by Mr Serfontein) mandated High Street auction house (respondent) to sell Thaba Phuti Safari Lodge by auction with a reserve price of R25 million. The mandate, dated 28 August 2011, authorized High Street to bid on behalf of the sellers up to the reserve price. The auction was conducted on 2 November 2011 by Mr van Reenen (the auctioneer). The auction rules, which complied with the Consumer Protection Act 68 of 2008 and its regulations, stated that sales were subject to a reserve price and that the auctioneer could bid on behalf of the seller up to the reserve. These rules were advertised in advance, available on the website and at High Street's offices, and read out at the commencement of the auction. Mr Ichikowitz (second appellant) attended the auction on behalf of Hansa Silver (Pty) Ltd (first appellant) (collectively "the purchasers"). He registered as a bidder and signed a registration form acknowledging that he had read, understood and was bound by the auction terms and conditions. The lodge was sold to Mr Ichikowitz for R20 million after bidding that included vendor bids by the auctioneer and bids from Mr Ichikowitz and a third party bidder, Dr Hoseini. During the auction, the seller reduced the reserve price from R25 million to R20 million. Three written sale agreements were concluded on 9 November 2011, with the total purchase price of R20 million. The purchasers paid commission of R2.28 million (10% plus VAT) to High Street. Hansa took occupation on 1 January 2012. After viewing video recordings of the auction in February 2012, following media reports of alleged misconduct at another auction, the purchasers claimed the auctioneer had engaged in sham bidding by making vendor bids without identifying them as such. On 15 May 2012, they notified High Street that they did not consider themselves bound by the sale agreements and demanded a refund of the commission. On 27 August 2012, while simultaneously signing second addenda to the sale agreements that provided for certain transactions and a credit of R2 million, the purchasers launched an application to invalidate the sale agreements.