refusal to exchange damaged item

I received a gift from my sister for Christmas ( a picnic chair) which she bought from takealot . I did not open the plastic package immediately so when I eventually did i saw it had a tear . My sister then contacted them to ask to exchange and they refused based on the fact that it had to be exchanged within 7 days of purchase . of course this would never have happened due to the fact that it was a Christmas gift. I then logged a complaint and they have treated me like i damaged it myself . Personally i avoid buying on takealot because previous gifts i received were always substandard and break easily . they sell poor quality products , do not support them and their service is disgusting