Why I want to strangle somebody - Part 2

Bring it on!!! I'm facing problems left and right now. I'm moving into a new house soon (hopefully). And when I purchased the house, I was supposed to get upgraded tiles. But during the construction, I noticed that the tiles that they fitted were the lower grade ones. Damn. When I asked the contractor, they realised they made a slip up and will rectify the problem for me. When I asked one of them, when this will take place, he sarcastically replied 'Are you gonna move in now?'

So I was thinking, 'Fine. don't want to piss these people off as they are building my house.' So now, after getting the keys to my house, they promised me they will get it done soon. But after weeks of follow up, they have now called me and told me they will not be upgrading my tiles, but instead will reimburse me a portion of the costs to upgrade the tiles. I'm like 'OVER MY DEAD BODY!!!'

I told the developer to go back to the main con-man/tractor and tell him what I feel. I'm not going to pay an extra cent to get this done. They have even given me the option to get my own contractor to do it and they will pay for it. I asked 'When will I get the money to pay my contractor? Before the tiles are laid or after? What kind of reassurance do I get that the main con will pay me? '

It's good that I have all these terms and conditions in black and white on my contract, still have some leverage on them.

p/s: Sorry there's so much angst in my last 2 posts.