Lack of feedback

I have been with Rodel since i bought my vehicle trough Renault (the 1year insurance you get with the plan). The 1 year is ending end of this month and I don't want to continue holding my policy with them. I phoned them and they advised that I have to send them a cancellation, the mail was sent to them on 25/03 and numerous follow up mails have been sent and I haven't received any feedback from them. I am really disappointed with the lack of feedback.