You can either set the change to be effective immediately, backdate to the beginning of the current billing cycle, or to the beginning of the next billing cycle.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
Hello Drp0417, being on top of your plan is vital, especially when it comes to your unlimited services. Please tell us more, which package do you have? When was the plan change scheduled to take effect? What exactly do the notifications say and when did you receive them?