Bad Timing and Lack of Notice for Major Upgrade

I look after 18 pharmacies and run our internet for all stores through Webafrica. They are doing an 'upgrade' on a Friday afternoon at Month End and now the internet is down all over. Was the implications for clients of this upgrade considered? How about running the changes overnight on the weekend or something to minimize downtime. How about giving clients more notice and details and perhaps a alternative solution. I phoned their support and Now there is no ETA as to when the internet service will be restored and was told we must just wait!. Not impressed.