I have had success recently with a bank and a telco by using social media, Twitter actually, to draw their attention to issues when their usual communication channels had failed to work for me.
Without being rude or unreasonable, I reached out to each via Twitter and this resulted in my concerns being put in front of someone who could help.
The outcome in each instance has been terrific – because the companies in each case had a structured approach to social media including monitoring mentions outside usual office hours. This is important as if having tried usual channels first – going out complaining on social media without trying other channels first is unfair.
Footnote: newsagents ought to note the need to respond outside usual hours as this is what people on Facebook and elsewhere expect. Gone are the day of the business being closed when the shop doors are closed.