Hey @B-Hill, The peak, should & off peak times will be shown in your contract / confirmation pack if you're already signed up. Each area & distributor varies, even the type of meter can effect what tariff you have.
Hey @BrentPatching , AGL stands for Australian Gas Light Company, which was originally set up in 1837! Wiki article attached for the history - https://en.wikipedia.org/wiki/Australian_Gas_Light_Company
Hi @skamella! You might not be able to get in touch with the original installers, but any solar service person will be able to advise you if there is an issue or if they're not working / needing clean etc.
If you log into the 'My Account' on the AGL website, you can find your bill under the 'Billing' section. If it's not there, it will advise you when the next bill is due. Still not appearing, I'd say give AGL a call to see if there is any issues