If you take to twitter Maxis officially says it allows migration from its Postpaid product to Hotlink so it's up to you to take it up with higher management. Once moved to prepaid you can then migrate to Flex.

Having said that, move to Flex only if you need no data or close to none. I moved from Digi Voice 38 to Flex 30. I could not finish my 1 gig data in 30 day with Digi but with Flex, 500mb already sapu in 4 days!

Not that they are cheating, but they charge in block usage so even if you use a few bytes, there will be a minimum and smart phones of today with multiple apps do that a few hundred times...