A: Do not be reasonable or polite, they count on that. Remember you're in the midst of a con.
No, no, no, a hundred times no. Always, always, always be polite first. Even FLAs (front line agents) have small, non-inconsequential, amounts of power that can cause you headaches. If you are rude and/or a dick right off the bat, they can do things like screw with your account, or "forget" to document some important part of the call that can cause you a lot of pain down the road to fix. There are times to get belligerent, the beginning of the call is *not* one of them.
B: Do not get upset or use poor language, that's a free ticket to hang up on you.
This is true, almost all companies instruct their phone monkeys that they do not have to take verbal abuse from a customer. Most institute a "three strikes" rule, where if you warn a customer twice and they continue then you are free to disconnect.
C: Waste as much of their time as possible.
Again, no. This is a high stress job. Wasting time for the sake of wasting time will just piss them off more and give them less incentive to help you, and possibly an incentive to fuck with you.
D: Never let them put you on hold.
There are times when FLAs *have* to put you on hold. The two main reasons are to transfer the call, or to speak to a (mentor | senior | team lead | supervisor | group coordinator | authorizer | ). Transfers are pretty self explanatory, however as someone who doesn't understand how call centers work, speaking to a supervisor may not be. There are various reasons why an FLA may need to speak to one without prompting from a customer, usually it's to obtain authorization of some kind. FLAs fuck up a lot, it's just part of human nature. When you have so many of them, it happens, because of this there are usually a smaller group of second level agents (I've seen ratios as low as 25:1 and as high as 50:1), that can go by various different designations, that FLAs can contact for help, or FLAs are *required* to contact to get an authorization to do something. Everything is monitored in a call center, maybe the FLAs have been sending out too many replacement cable modems lately, or maybe there is a company edict that credits of a certain amount must be authorized by second level agents. They need to put you on hold to do this, they can't do it while the line is active, period, because technically customers aren't supposed to even know these second level agents exist, and if you ask for one, you will never get one.
The best advice I can give, is to just state what you want, if it's not being delivered, ask for a supervisor. If the agent offers any kind of upsell, just decline it politely.