Hi @DebbieVG,
Great question! Your account will update automatically if your active contact number jumps into another pricing tier. Whatever the highest number your active contact number is listed at during a billing cycle is what will be charged. I would check out our pricing page to see how the costs will change as you add more contacts.
Hi @DebbieVG. I'm glad that Nick was able to help you out. Let us know if you have any more questions!