Oh how entitled we all seem to be.. You do realise that smartphones cost a fortune and are often offered on very cheap monthly contracts? These are businesses, not charities. The networks rely on a break even point of about 22 months and then hope you spend extra per month above your "free" or "included" benefits to make a little bit of profit.
Take for example R100pm contract x 24 months = R4800. For that, you are given a R4000 phone and about R600 worth of voice/data. Are you really worth their time if you only give them a R200 profit over 2 years? Now you want to cancel early. You need to obviously pay off the full device cost, because you are keeping it (R4000), then what about the minutes and data you have used that were subsidised over the full 24 months? Not to mention some of the extra freebies that some networks offer like additional data, covers etc.
For some reason, people feel they should only pay for the phone and that's all. It is far more complex than that.