it's more like a backdoor for them if they ever wanted to end
the incoming calls thingy.
if they say forever and want to end it later, how? they can get
sued.
so best is they extend it if permitted, if they wan to stop the
promo they can continue to honour it until the period is over... at
least they can say, we told u it'll end on that date and not get
into legal implications.
