That doesn't sound right! Sorry about the hassles you're having!
Let's try and troubleshoot your connection. Would you mind taking a look at the relevant link below and then have a run through the troubleshooting steps it outlines?
If that doesn't work, I'd recommend getting in touch with Optus Technical Support via phone or live chat (http://yesopt.us/chat2us).
Let us know how you go! We're here to help.