Salary deduction disappointment

So i optes for the salary deduction with my insurance,I received my iemas statement and saw that they will be deduction three months premium end of april,i never agreed to that i was not even phoned or emailed about that amount.Iemas must call me and let me know how i will survive the whole of may since they will be deducting so much money and another thing it is impossible to get hold of them they also take timw to reply to their emails.