Hello, I was wondering if any knowledgeable people could give some advice on an Indian sandstone patio im having put down?

Its a small paved area and was started today. There is grey chip stones as a base and then sand mortar. It's yet to have the pointing done but the issue is that alot of the slabs are slanted. The corners dont evenly match each other.

I texted the builder this evening, concerned that it would set overnight and not be fixable. He's seen the pictures and says its not a perfectly even slab and they have different thicknesses to them and its fine as they're all the same going by the middle point of the slab. I disagree, while i understand it wont be perfectly even it looks really quite off with a noticeable slant or drop in height between each slab.

Whats everyone's thoughts? Should i ask him to even them out or is this normal? The slabs also dont follow the string line and he said not to worry its just for height. I also noticed a hole underneath one of the slabs with no mortar underneath.

Thanks in advance for any input.

the string line is to indicate "level" and "height" ....patios are installed "out of level" so water can drain off - and away from your house - check if that is true ...if the the installed rock is higher at your house foundation and lower at your yard - then the installation was done correctly

the gaps between slabs will allow for expansion and contraction, when subjected to changes or extremes in temperature

I would let the contractor finish the job - get some kind of a written guarantee of workmanship or defects ....(a verbal guarantee wont work)
then wait for the next heavy rain - if any stone sinks, or there is any ponding of water at the house or anywhere else in this job - then call the contractor back to fix the problem

I agree. I don't care for the big height differences. Thickness of a stone can be fixed with the thinset underneath. They should be able to make the stones level match. If the contractor is registered, and doesn't resolve the problems to your satisfaction, call the Registrar of Contractors. They will inspect and step in to help you.

As you are indicating that is going to be a permanently mortared in paving stones, DO NOT let the pointing be till YOU are satisfied.
I cannot see the bubble on that level but if they are leveling across the highest point of each slab that is the norm but there should be NO air gaps under any stone as the one pictures show and those slabs are cock-eyed ,not even close to level any where as the string line and picture show. s
It also appears the high point is on the outer edge so water will flow towards the door unless the house is cock-eyed and pavers are level.

There should be nothing between the pavers and that wall but sand, much less weeds.
You are getting a half-arsed con job, start over.