I just got charged the 10 dollars for the texting bundle but I had planned on switching to the 20 tomorrow. If I do will I be charged the full 20 or will they just take another 10?
The best thing to do is call customer service at 1-888-294-6084 and ask them.
Anytime you change your plan or feature you are liable to be prorated on the change. You will be charged for the portion that you use from the old and what you used from the new.