You receive Twitter notifications on your phone but don't remember which Twitter account your phone is associated with.
While trying to add your phone via SMS, you accidentally created a new Twitter account by typing SIGNUP instead of your username.
Troubleshooting
Navigate to twitter.com
Click on the Activate your account link located on the home page as shown below.
You will be directed to a page where you are asked to enter your phone number. Enter your phone number along with the country code.
If your phone number is linked to a Twitter account, we'll send your phone a text message containing a verification code.
Use this code to confirm that the mobile number belongs to you!
On the following page, Twitter will ask you to fill in any missing information for your Twitter profile. Your username will already be filled in. That username belongs to the same account your phone is tied to.
Want to remove your phone from your Twitter account? Read this article for help.
