Thanks for all the advice After the run around I have discovered the following.
I do not have a dividing boundary dispute at all

given the fence was constructed nearly 12 mths ago it is argued that there exists no dispute as to it,s being there..
what I do have IS A minor civil dispute

the burden of proof is a reverse ownus, so i put my receipts forward and they can claim that they do not/did not want / have not / will not benefit from or have no requirment for the dividing fence. Best part is that because it is a boundary fence they are actually 50% owners by fencing laws weather they like it or not. so good luck proving it's not for them

and the $1200 for 75mtrs of fence is far less than the cheapest type of fence you could find. works out at $34.00 per meter and they pay half.

And a verbal agreement is sufficient grounds for a minor civil claim,
and the previous fence was replaced as the dogs got into each other and council laws state that dog owners must have adequate fencing under the ACT and if any part of the dog can get under/over through then the fence is not deemed as adequate.

So my facts are
Verbal agreement
Failure to pay
They are 50% beneficiaries of the fence.
They have a requirement under the act to have a dog proof fence as per council regs.
So I have just done all the paperwork and will lodge with court on Monday $114.00
Then the best part is I HAVE to personally serve them LOL and fill out a REG 9 affidavit

So I will put the 2 sections of fence back in morning as he who laughs last, laughs loudest

Oh and council rangers have been called regarding the threat to incite a dog fight apparently that's an offence....somewhere to knowingly incite animal fights. Oh and you need a breeders licence to bread dogs / oh and you need permission for 3 dogs. Oh and your stormwater needs to be plumbed in to pipes not dripping on the ground from shed / oh and its an offence to not have your septic hose on .
can't wait for this

Jet