I wanted to cancel a non-contract line from my mobile share plan due to low usage - its my own equipment and I was paying $15 a month + ourages taxes. I called in and the CSR cancelled for me on that day, no problem! no issues, right? until I receive that month's bill...
That cancelled line was on a $40 - $25 discount monthly bill, when I cancelled it in the middle of the billing cycle, AT&T took out the $25 discount entirely! So instead of pro-rated from the $15 plan, I was pro-rated at $40 for that month and ended up paying more than a full month.
I had to call in again, twice, to explain the situation. Both time, the CSR insisted that once a line is cancelled, all discounts will be taken out. The supervisor was always conveniently "on the other line" and never available, and they refused to do any adjustments to the "cancelled lines" with very bad attitude.
I guess lessons learned, AT&T will add you a line within a heartbeat but when it comes to cancellation, they would try to sneak into all kinds of gimmick and what do they care about "cancelled lines"? nothing, you are not their customer any more and you are not worth a penny so why not charge as much as they want?! sure, what can a "prior" customer do? nothing...
Good strategy and good way to keep your loyal customers happy.