If you can't access to my account in the web, it might be because you didn't activate your account. 

Note that, as a common step when you register in any web, is the validation process. This step is for your own safety, otherwise everyone could register in any web with your mail. 

Please, look up in your mail in the different folders you have. You should receive an email from no-reply@rift.gg. This email can take a few minute to arrive. So, if you didn't get It inmediate, please be patient. If you do not received this email, please get in contact with support@rift.gg informing them you didn't receive the vailadation mail.