Williams 7.2

The first sentence is less clear. Perhaps the vagueness of the sentence leads many to misunderstand and not cancel their free trial offer and therefore be charged the first monthly fee. The simplest way to write this sentence would be "If you don't cancel your membership within the first thirty days, you will be charged the first monthly fee." But that sounds more like a threat. The company wants this part of the contract to feel like an option, not a warning.