well just go the sales of goods act method then
" Q4. I know I can demand my money back within a "reasonable time" but how long is that?
The law does not specify a precise time as it will vary for most sales contracts as all the factors need to be taken into account to be fair to all sides. The pair of everyday shoes may only have a few days before the period expires but a pair of skis, purchased in a Summer Sale, may be allowed a longer period by a court."
your normal i want my money back for most shops is 14 - 28 days but just use sog and you cant loose