There are a number of reasons why your electricity bill may not appear to go down after you get solar.
1) You could be using most of your energy at night, meaning that the majority of your solar is being exported to the grid (and you are paid a feed in tariff for it). Exported solar is worth roughly half that of self-consumed solar - so you would see a more significant saving if you shifted your energy usage to daylight hours.
2) You're simply using more electricity than you were previously. Solar can offset the daytime energy usage in your home - but if you simply increase your energy usage in the belief that solar will offset it all, your bills will be higher than they were previously.
3) Your system is not functioning properly. The company that sold you the system should be happy to come and check everything is OK. But if this is not possible, here's how to check it yourself.
If you're determined to get to the bottom of this, we can recommend someone who - for a small fee ($100-$200) - can come to your home, perform a simple energy audit and make recommendations.
If you would like us to do that, just contact us. Be sure to include your postcode and phone number.