Your free period starts on the day that your service is activated (you can connect to the internet).
After the promotion period, your service will change to the full price of the broadband service you chose when you placed your initial order.
Brsk bills you ahead of the period and you have likely been billed a pro-rata amount for the period of the billing month that your free period does not cover as your trial.
For example:
Your promotional period starts on the day your service goes live. Let's say for example your service is installed and goes live on 27 June, and you have selected the 1st of the month to be your billing date, but have qualified for 3 months free.
Your promotional period starts when you are installed on 27 June and ends 3 months later on 27 September. Your billing date is the 1st of the month. Brsk bills you in advance. You will receive a pro-rata bill for £0 on 27 June and then a bill for £0 on 1 July and on 1 August. You will receive a bill on 1 September for the pro-rata amount due for usage of the service from 27 September to 30 September, as these days fall outside of your promotional period and fall within the billing cycle starting 1 September. Your next bill, on 1 October, will be for the full monthly amount owing as this pro-rata payment has normalised your billing cycle to run from the 1st to the 1st of each month. You should, therefore not see any further pro-rata values come off of your account for the BetterNet.