Immediate cancellation of Policy without my permission!

I gave a notice of cancellation of my insurance on the 5th January and I paid for the month January and told the consultant telephonic-ally that my policy can laps on the 31st of January. To my surprise i received a letter saying my policy lapsed on the 5th of January. Yesterday when I phoned the call center the consultant i Spoke to was very rude and even dropped the call while I was Talking. This is unacceptable!