If you have suddenly lost Premium access, it may be that you were signed out of your account. It's very easy to check this. If you are signed in, your username will appear underneath the Chordify search box in the left-hand side bar. If not, you will see the text "Log in" and you will need to click on the link to do so.
If this doesn't do the trick, it is always worth checking that your payment went through and that there are no issues with your chosen payment method.
Should you still have problems, please contact us, letting us know the e-mail address associated with your account and the payment method you used so we can get you back up and running in double quick time.