Wheelchair will not open fully

I have a Carex wheelchair for only less then a year, and the problem with this with wheelchair is that it will not fully open or will not spread apart at all. Upon looking closely or inspecting the chair as I push it down to open fully, I notice that at times the left or the right will not slide down, which prevents the seat from collapsing down to open fully. Because of this I am uable to open my wheelchair to open fully to allowed me to sit. At time when the wheelchair would only open halfway I have to sit in it in a tight position and Hopeing that with my weight it would force it to open up, which it dose sometimes, but now it will not open anymore. The part in which it needs to slide down which is the left and right is stuck, I tried WD40 by spraying and lubracating the bar and forcefully pushing the bar down. It work , but for only 4 days, now it’s back to square one. Is there anyone in the ifixit commmunity who are familiar with wheelchari repair, or knows how to disassemble the wheelchair? I have continuely have contacted the company (Carex) for support and help as to how I am able to repair this problem, but I have not heard or recieve any information at all. I do not want to pay addition $500 a new one, since this one is not even a year old. Please help. Thank You.