Yes Boonping they charged you installation of RM50/- They tricked you into asking for their assistance. They agreement says that they will charge you RM50 for their services if you encounter problems and ask for their services. (btw the credit adjustment of RM50/- in your bill  has nothing to do with the installation amount. It is a rebate given to everyone who register online - applicable at the time you subscribed to the package).

From what I see, this is their trick (I am not claiming it for a fact, just they way I think is happenning) :-

1) When you subscribe for OWN installation package, they purposely don't jumper or do bad jumpering job so your modem no signal.

2) They then convince you that your side got problems so that you will agree to ask for their services (they consider this as 'Installation services')

3) When you agree, they will arrange for their contractors  to come to your place. After that their contractors will call up TMnet and speak to thier 'inside' people and pretend they are doing something to solve the problem. All that is happenning is that the contractors just give the 'ok' signal to the inside people to proceed and jumper properly so that your modem will now have the DSL signal.

4) They then charge you installation fee for your next bill.

After that you can use your own imagination, how much 'share' they get.