Seriously impossible to cancel your insurance policy!!!!!

This is seriously ridiculous!!!! I've been trying to cancel my Father in law's car insurance policy as he have sold his car and dont need his insurance anymore, but without any luck...still struggling to even get a call back! He doesn't have a phone so he asked me to contact Miway on his behalf. I understand that I can't cancel the policy without the policy holder but that's why I've been trying to get someone to call me when I get home, a consultant..cant remember the name...told me she would arrange that someone call me at 17h30...I'm still waiting!!!! I cant even call back everytime because you only buy certain amount of airtime and to be hanging on their lines waiting for someone to respond could seriously take hours!!! Once I've been holding on for more than 15mins!!! Honestly..time wasting!!!!! What else do i need to do to get someone to cancel my Father in law's insurance???????