I'm confused as to why your sister-in-law should want to contact Nokia. If a product is faulty, the law states that it's the
retailer's responsibility to put matters right, not the manufacturer's. So, if your sister-in-law got the phone from Asda, for example, she should complain to them, not to Nokia.
If she insists on trying to get Nokia to rectify the problem, she should take her phone to the nearest Club Nokia service centre:
http://www.apps.nokia.co.uk/clubnokiaservice/
Like most major companies, Nokia don't publicize an e-mail address for customers to contact them. (This is an anti-spam and anti-hacking measure). Instead, they provide an online form:
http://www.nokia.co.uk/A4222232
If that's not working, why not simply phone them? It's only a local call rate and the lines are open from 0900 to 2100, Monday to Friday:
0845 0455555
Chris