Hi
Firstly welcome to the forum
Regards to your stilts I would suggest that you go for the next size up as the ones you have will be no use to you and there's no way round it sadly! This would be the case for any brand!
Also About Skyrunners...
If you are in the UK, and you brought them from a UK market - They are illegal and therefore I would go back to the place you brought them from and tell them if you don't get your money back you will be getting the trading standards onto him as they are not allowed to be sold in the UK, you should also email webmaster@powerskip.de (who are the patent holders) and tell them exactly where you purchased them as they would like to ensure that no illegal trader trades in the UK.
Why are they illegal?
The jumping stilts are a patented product, therefore all sellers in the UK must pay royalties to sell them, this ensures quality control and also gives something back to the inventor.
In the UK skyrunners are illegal as the patent holder has not granted "Skyrunners" a right to sell them. Also Skyrunners are said to be of a lower quality than other stilts available, some get a good pair others are very low quality - it seems to be pot luck.
Hope this helps