Will Aviva Explain Reckless Increases in MyShield premium?

I am shocked to receive a premium demand for my MyShield policy from Aviva which is significantly higher than the prior years. I bought the policy in July 2012 and paid a premium of $481.46. In 2013, I was asked to pay $800. This year, the amount has been increased to $1129.63. Should I expect to pay $1500 next year? And $1900 the year after? Where will this stop?

Can anyone at Aviva explain the basis for these reckless increases in premium every year for a healthy man with no claim history?

There have been regular reports of insurance companies in Singapore arbitrarily increasing medical insurance premium for hapless customers. Is there any authority or agency in Singapore which can rein in these companies? Is there any regulation here to control these companies' behaviour and to ensure customers are not taken to ransom?

I have written to Aviva. Will share the reply here if they reply at all. Keeping my fingers crossed.


Update on 1 Aug 2014 at 7.20 PM: Aviva has not bothered to reply to my email yet which was sent to their "customer care" email address.