We understand the change may have been unexpected and we'd love to clarify a few things.
To make sure we can continue to deliver the best possible experience to our customers, from time to time we review and adjust our plans to reflect ongoing investments in our network and our service. Whenever we make this type of change, we do notify you at least 30 days in advance.
In line with our terms of service, the price of your add-ons or month-to-month services (such as Value Packs) may change. Since we must let you know of the price changes at least 30 days in advance, we notified you with a bill message.
I do hope that info helps!