PREMIUM INCREASE WITHOUT PERMISSION

I have had a policy with Metropolitan for years. And when my acc was debited this month 22.05.2018, the amount was more than double the amount its supposed to be. I called the customer service line on 23.05.2018 to enquire as to why they had deducted the incorrect amount, i was informed that my premium had increased? This is alarming as i never called in and never received a call from anyone to inform or even request any changes to my premium. I am now the one who will be inconvenienced as i need to make out an affidavit, make copies of my ID, etc. in order for Metropolitan investigate an error on their side?? Where did the consultant get my details or the authority to make changes on my policy??? ********** 004768