Penalty is just a subsidy recovery.  Ask any of the digi center people to show you the calculation.

its retail price minus subsidized price - which is prorated based on amount of months you have left on the contract + RM100 admin fee.

Which means... if your phone RRP is RM1000 and you got it for RM500 on a 24 months contract, if you quit halfway at 12 months

it is...RRP-Subsidized price = 1000-500 = RM500,
then prorated 12 months left on contract = RM250
then +100 admin fee = RM350 contact termination fee.

Which is quite OK cos

1. They don't charge you for the remaining service which you never use
2. If you look carefully all they are trying to do is recover a PORTION of the subsidy they provided for the phone
3. Even after you terminate halfway or whatever - most of the time you still save money vs buying it outside without contract