Depending in the country you're in you can demand a refund if it's not fit for purpose.
Here's a link to the Australian consumer law
http://www.consumerlaw.gov.au/conten...tees_guide.pdf
Page 7 of that is particularly interesting, as it talks about refunds.
If it's a major fault, as a consumer you have a choice to get a refund, regardless of what Kobo say.
This may differ in your country.