Do I have to renew a free account?

Finally, do I have to actively renew the free service if I stay within the set limits? i.e. will the free service just continue without any interruptions until I reach the set monthly limits at which point I understand that I would have to upgrade the service? 

You do not need to renew your account when you're using the free service, as you're not being billed. 

You're correct, the service will work as long as you do not reach your limits, if you reach the limits then you will need to wait until the first day on the next month to get the limits reset, please do note that this is in EST time, but if you need the service to continue working even when you've reached your limits then you will need to upgrade to a plan with the needed limits. 

Your free account will remain active until you decide to delete it (deletion of account should be requested to us). 

If you have any question, please let us know.