MWEB presumably free fibre connection

I signed up with MWEB Fibre on 26 October 2020. My account was activated on 6 November 2020. MWEB is running an adverti*****t on their website that the first two months on subscription to MWEB fibre is free. On 07 November 2020 MWEB invoiced me for the amount of R665.83.

Upon querying the invoice I got told that their 2 month free promotion only ran from 01 November 2020 and because I signed up in October I am invoiced the pro-rata amount for the month.

How is it possible that a service is only delivered on 6 November to be invoiced if the delivery of the service falls inside their promotion period (according to the enquiry)