Pvc window multipoint lock

[Naymay]

Help please anyone!
My window lock was broken so my flat ate ordered one off eBay and decided to change it over herself. It seems the new multipoint lock is much larger that original broken one and she forced it to close and now it's stuck. Their is slight movement and a gap around edge with window pulling to one side

 

[pinenot]

The only help you need is getting the window lock unstuck, can I assume that that pulling on the handle does not provide enough leverage? If so can the handle be removed to expose a square spindle and a set of grips locked on to increase the leverage. Otherwise some way of extending the leverage on the handle, which unfortunately may be marked or broken this way...pinenot