@Tamara2018
Have you ever created a self serve account before, if not you can register for one here:
https://selfserve.publicmobile.ca/self-registration/
If you have created a self serve account and you are having issues logging in, try clearing your browser's cache, or try a different browser or device. Opening a tab in incognito mode may help as well.
Also, too many failed attempts may temporarily lock your account access. So wait 15+ minutes before you try again.
Then try the "forgot your password" option: https://selfserve.publicmobile.ca/forgot-password/
If suspended for over 90 days, then you lost your account, phone number and access to self serve.
If still a current customer and still having issues, contact CSA by methods provided by @softech