Breaching policy

I opened a Mr price account recently and after a few days I was called in connection with policies. I accepted them. I then changed my mind and went to cancel a few of them. This is where the problem comes in. I was told and I have it in writing that if I cancelled within 30 days there would be no cost yet I am being called and sms' are being sent to me asking me to pay for these policies I cancelled(within 30 days). The *********** staff have now called me 3 times. Each time by the wrong department despite being told they would get the insurance department to call me. I went into the store a week ago and was told the insurance department would contact me yet nothing has been done. My name now looks bad because Mr Price employees do not know how to do their job.