Incorrect cancellation

I must say I am deeply saddened by the service I received from Old Mutual, a while back I sent an email querying the cancellation of my policy since I have a certain medical condition, all my other insurers called me and discouraged cancelling since the illness came after I took out insurance, of which they came after Old Mutual, however Old Mutual didn’t even bother with a call to verify anything, I just received an email saying the policy has been cancelled and they will refund me my previous premium, whereas the policy could have just been updated, can you reverse the cancellation and update my policy accordingly