The pricing of the system is based on the number of contacts stored in an account, on a month by month basis.
There are brackets of contact numbers which affect the monthly cost of an account as seen below:
If the volume of contacts in an account increases into the next bracket, the system will detect this and move the account to the next pricing tier.
If the volume of contacts is increased via a bulk upload (file upload), you will receive a warning that this pricing increase will happen and won't be able to proceed unless the confirmation checkbox is ticked. You can find our current pricing here.