Bosch Siemens home appliances failing to meet their guarantee policies

I am Sandie Magubane and I bought a Bosch fridge freezer at Stax fourways on a closing down sale in 2015, the salesperson and the manager told me that the guarantee will be carried by Bosch Siemens home appliances. After a few months the fridge started to give me problems and I called Bosch SA they sent a Technician to come and fix the fridge. But after that the fridge was continuously giving me the same problem they even took the fridge to their workshop for 4 weeks and gave me a loan unit. The fridge has been repaired 8 times and these are the job numbers Bj. 068347, 072601, 075603, 096418, 106889, 114995, 122279, 127331. My complain is that I don't need that fridge anymore. I want the unit to exchanged but now they want to exchange the unit with an expensive one. They are saying I must pay a difference and I don't want to pay any difference all I need it's a replacement. Sandile Magubane cell ********** , work no. ********** .