Mobile phones don’t cause cancer.
This is a bit of a weird article, because you mention right at the top the IARC (the WHO’s cancer body) rating of mobile phones, which is 2B. Funnily enough, this makes mobile phones safer — in terms of cancer — than stir-fries, being a hairdresser, or eating red meat.
You can find the WHO recommendations about mobile phones here. Basically, there is no reason to believe that the radiation emitted from mobile phones poses any risk to our health. After 30 years of accumulated data we can say with quite a bit of certainty that there’s no link between mobile phone radiation and cancer.