You have not said what the allegation was, and that's alright, but to be stood down the matter must be serious.
Are you in a union, if so they may be able to proved you with legal assistance, if you are not in a union, or the matter has nothing to do with your job, you still need legal assistance.
This sound more serious than something a community legal centre may be able to assist, you need to consult a solicitor who deals with this sort of matter.
If it is criminal matter search for a criminal lawyer locally, if you need assistance doing this consult the Queensland Law Society for assistance in finding an appropriately qualified lawyer.
This is going to cost you money however many solicitors will provide an initial consultation at no charge and provide you with a quote of their costs to take on your case.
You may qualify for legal aid, the solicitor will advise and make the application for you if you wish.
Sounds like they are claiming you drove off when the police tried to stop you, and you left when they called to interview you about the matter. The fact that you have been suspended suggests that you were driving a work vehicle when the police tried to stop you.
You were in the wrong if this is the case, the least expensive way of getting out of this is to pay the infringement notices.
You have to stop if the police direct you to do so, driving off is an offence, to walk off when a police officer calls to see you is also foolish. You do not have to give any replies that may incriminate you, no comment, is the reply when asked such a question, however running away is not on. You have received infringement notices for both of these offences.
As far as you suspension goes, if you were in a work vehicle when you committed the original offence, you may be dismissed. Take this up with your union. If you have failed to join one, this is another error and you may suffer the consequences, see a lawyer for assistance, but don't hold your breath.
Because it's not a good excuse to leave the scene and it's something you have to explain and defend. Depending on circumstances, it's understandable someone may get angry and confrontational - maybe you almost ran him over? It may have been an entirely appropriate human response, and maybe you're lucky not to be charged with something else more serious.
True, you would be trained to leave a scene if you are at work and someone approaches say the front counter and is aggro. Did this aggro happen at a counter, or did it happen at an RBT stop? Because I would say if you were driving a work vehicle and stooped at a RBT, driving off would NOT be good. We'd need more details of what happened and where.
It was at an RBT site & I walked back to the work vehicle after standing behind the police car after the cop got aggressive ( put the cop car between us). I asked him very calmly if I could go and he just kinda sighed ( a bit like growling under his breath) I then said 'oh well I'm going' and waited maybe 2-3 minutes and slowly walked to the work car, then drove away and he never looked at me once.