Instruction: Answer the given question using the supporting document.

Input:
Question: My siit upon llost it't air. Can I pump it up?
Document: I liked the sit upon as long as it lasted, I only lasted 1 day for one of the and a week for the other.
I found the sit upon to be benefical when sitting for lengthy periods at the computer. I also use it when I am doing needlework. I now have a happy back. :o)
I just put it aside for a while and it gains a little air inside which makes it usable for me....wish I would have noticed the fill needle among all the bumps, but I didn't.
This product definitely helped with my posture while sitting at my sewing machine or computer... No more slouching. Plus it works some little muscles in my back because it allows your weight to shift. The only things I didn't like were that when wearing shorts the bumps were uncomfortable so I had to lay a cover over the Sit Upon. It also got hard feeling after a long while... Reason to take a break and move around!
I bought this....There is too much air in it, it makes me feel like I'm balancing on top of a ball, and puts me too high for the petal of my sewing machine (I have very short legs). I finally poked a hole in the side with an ice pick and let out most of the air in order to use it. I wish I would have spent my money on something else.
When at a quilt-in, I tried one that my friend had. She strongly recommended it because my back was giving me so much trouble. When I sat on hers, I felt like I was falling off of a rubber ball. But, I decided to get one anyway because my back was giving me so much pain. The one I received was a newer model and seemed to have less air or gell, or whatever, in it and it works much better!
I ordered it , as a fellow bus driver swore it helped his back.I received it  very fast from AMAZON, put it on my bus on a Monday, and 1st of all it was very hard to balance on.secondly , on the 4th day, Thursday, it 100% deflatedno cracksno holesit just lost all of its inner air,However AMAZON gets 5 stars for its  hassle free & free returnsstill looking for that ultimate back saver cushion
Found it was a great disappointment. No instructions in fact no paperwork whatsoever. It was so hard when you sat on it. Finally ended up letting some of the air out of it just so you could sit on it.
This little disc shaped air cushion keeps pressure off the spine and causes you to continually adjust your center of gravity in order to stay balanced and upright. These small adjustments improve your posture while preventing back pain from sitting too long. It works.
I read reviews of others for whom this did not work, but it sure did for me.
Answer: Mine also lost air, I pumped it up once but when it lost air again I could not pump it up.  I have just recieved a new one directly from the Gypsy Quilter.  I emailed them and they said I could send it back and they would send a new one, I will see how this works.