Charges and Variations - again!

Trying not to make this an angry post.  We didn't get a handover date because our SS is not well although he texted letting me know he was unwell and was waiting on a gas and electricity update.  So even if he wasn't unwell he wouldn't have been able to tell me anything anyway

In the meantime our customer services lady emails an email with an attached variation.  Again something she sounded surprised that I wasn't expecting it.

Here is the content of this variation (Building Variation 4 - note we didn't sign Building Variation 3 which was the whole trench fiasco which you can read more about in this post)

According to the contract clause 12 we should be given notice 'promptly' and implied that it should be prior to the work being done.  The work referenced in the building variation was completed in December or even November in 2014.  It is now 12th May 2015.  

We already have in our contract the following with relation to services in the trench (snippets are from Post Contract Variation 03): 

Extension of power (and telstra lead in) for our long driveway as well as allowance to hand dig around posts is $5934.

Provide 25mm gas line with path valve to the property to service the dwelling $5574.

Optus conduit in an existing trench at $1500.

Given the conduit is just plastic conduit like this (from Bunnings) and with retail pricing costs $7.64 per 4m length and assuming up to 80 m for the street to the house - which is super generous materials would be $152.80.  Labour would have been an additional 1 hour.  But say it is 2 hours to drop in this extra length of conduit and put a draw wire through).  I'd like an explanation of the $1500 being charged when we specifically asked for the removal of any overhead poles to not affect our costs and given the cost calculation I just did.

Note that we did our own trench and I would expect some of the above charges are based on the trench being dug given part of the inclusion of 1-6 was allowance to hand dig around posts.

Most of the above is from an email I sent to our Customer Services person around this matter as a bit of a 'please explain'.  I'm still waiting on a written explanation and response from Sekisui for Building Variation 3!

I'm not trying to make excuses for them but I still like Sekisui.  But this does make me feel they are trying to really 'try it on' with us.  I do hope it's not common practice for them!  

I've been trying to find a clause under Fair Trading or ACCC which may talk to unconscionable conduct or predatory pricing or expression of market power or something.  It's been a while since I studied legal stuff but I'm sure there is something there.  Surely they can't hold our home to ransom (not that I think they are trying to do so) and try and get some more dollars out of us.  It's already a $380,685 total from a base price of $189,200!

For those who are curious, the variations we had and have approved are:

Post Contract Variation (this is the one after signing where they 'fix' all the bits up including any BASIX requirements): $6029

Building Variation 1 (extra fill): $2150

Building Variation 2 (rock excavation for storm water) $288

Let me know if you have any ideas where to look for the legal clauses I need as a back up :)