Looking for Phone verification experiences on Google/Facebook and others

Hey guys, im very interested in getting all the info you are willing to share on phone verifications, for example: if i buy 10 phone numbers to verify accounts with:
-can i verify endless accounts?
-if not what happens when i reach a certain number of verifications from that number - will the previously verified accounts be banned or only the number?
-is the number reusable after some time? ( for example i verify a google and faceebook account and after one week i verify another one with that number)

Im very thanksfull for any information you could share with me! thanks =)

-No you cannot. For 10 numbers you can verify 60 Gmails and 10 Facebook.
-No they wont ban you or anything. Just they won't send the code to that number and asks for another one.
-Yeah, may be after a year the number becomes usable in the case of Gmail.

does anyone have experiences with google voice? does it still work?
i would love it if there was a service that would send verification codes like captcha solvers solve captchas =)