Looking on the internet deeply has found these results:

I don't believe I have done it. is the most popular phrase on the web. 

Related Comparison

• i have not done it or i did not do it?
• I have did it or I have done it?
• i don't have it or i don't take it?
• i hope you had enjoyed it or i hope you would have enjoyed it?
• i don't have it or i won't have it ?
• If i were he i would do it or If i were he i would have done it?