what are the dangers of the orders cancellations? Please tell me about the disadvantages of it?
Here you go - from the Customer Services section of the main Fiverr website, where you can find most info:
It is probably the worst thing you can do as far as your rankings on the site. Worse than a one star review.
However it cannot be helped sometimes. There are times when you have no choice but to do it. Your gigs will recover after some time.
I have completed 10 Orders and my 3 orders have been cancelled. So, can you please tell how much is my cancellation rate?
You may check the same under the dashboard of your profile.
Brother their is indicated that orders completed percentage is 87%