Every time I top up my Happy prepaid SIM service I get a bonus but I never seem to use any of it.

Does it continue to increase indefinitely or does it expire?

How do I use it up?

Thanks.

Call other DTAC mobiles.

That simple?

I guess I don't know any other DTAC users.

Thanks.

You can use it only to phone other Dtac customers, yuo do not have to have any credit on the phone to do this either.

You cannot use it for any other services liek SMS only call Dtac customers

It does 'rollover'.

Rather underhandedly, they removed the T&Cs of the Bonus program. What used to happen was that any Bonus calls were made at the same rate as your tariff. Suddenly all Bonus calls were charged at 2 baht per minute regardless of your tariff, but there was nothing in the T&Cs to indicate such a change. In fact the T&Cs mysteriously disappeared.

I made them compensate me fully for this underhand behaviour.