Not saying there isn't the rare company where one can be genuinely honest and genuinely care about the customer and succeed. But I suspect such a company is rare.
And in telecommunications, perhaps nonexistent.
In any competitive industry (and telecom is one), you have to lie or color the truth in order to provide enough incentive in order both to overcome suspicion of the telemarketer, and for anybody to want to take the risk of switching to you. Especially in telecom, where people have been burned plenty of times before.
That's not to say you can't eke out a living. But as far as being one of the richly-rewarded top producers, forget it.