not honouring guarantee

Purchased a clock from them end September 2015. It stopped working end December. We returned from leave and then I searched for the slip. Eventually found it and took the clock to them yesterday, told them it was not working and would prefer to have it replaced. Only one lady working at the front. She disappeared to the back and obviously spoke to someone else. Came back to the till point and phoned someone, finished, disappeared to speak to the person at the back and then came and told me the guarantee was only for 3 months. Bad luck. I told her I believed in terms of the CPA she was incorrect but she said they would not replace it. Later went onto cpa site and there it states six months. Refund, replace or repair.<br> We are only in Hoedspruit on weekends. Came back to Tzaneen, phoned Mr Price as Sheet Street is one of theirs so I believe. Told a very helpful lady the clock story, when it was bought, let her think it was from MRP and she said no problem it will be under guarantee so bring it back with the till slip. Nice run around by Sheet Street if this is the case. I want clarification from Sheet Street about this as am very unhappy about being messed around.