Please, help me overcome my ignorance.

I got a new oak tile floor done by a professional. The floor is a disaster. It is full of chipped tiles, many are not laid flat, laid too far apart or not squared in 4's. Water will spoil the floor if accidentally spilled, insects will move in anytime.

I wanted unfinished tiles but the contractor changed them with the excuse that "i had chosen that color" without telling me that they were of different quality. (He does not tell me where he bought them. Is this right?)

And now the contractor wants to fix it so: 'inject glue under the tiles that stick out' and then 'sand and coat with poliurethane.'
He wants to sand tiles that are pre-finished. Is that correct?

The floor is wavy, due to no preparation of the subfloor.

Am I being ripped off? How can I defend myself from having to accept this bad job?

Pictures of floor details on
https://picasaweb.google.com/106926649009544773702/Floor

forget all the drama of right and wrong and ripped off.im sure you paid for exactly what you received.

if he is willing to homor it and make corrections than that is where you need to be at this point.what else would you expect?if the job still isn't acceptable then
you take it from there.

yes you can sand prefinished flooring. this is what you wanted to begin with.
since he fouled up, he can sand it it and make it smooth.
he can resecure tile.but ideally he should just pop them up , reglue and set or replace with new one.

some of the corners are way off..but truth ne told..corners are never perfect with parquet. NEVER.

the chips and voids can be filled.

I agree he was definitely lacking skillful tech nique setting them and damaged excessively in some instances but it can all be corrected.

the floors can be troweled filled with glitza wood flour and made seamless.

don't know if he has the skill.
but you picked him. don't expect an internet forum to save the day

I totally agree with the reply,... You wanted ray to begin with,... but I'd be very temped to Full trowel fill is with Wood-Wise Wood Patch -Not the shrinking watered down Full-Trowel version.