Where do I start... .the log cabin arrived after a...

Where do I start... .the log cabin arrived after about 12 weeks (they said 8 but I was ok with that given the current situation) in 2 deliveries.....lots of parts but unlike an Ikea piece of furniture no plan on how it all goes together .I enquired about them building it for me before I placed the order but was told they don't do builds.
I had prepared that concrete base and it was a close to level as concrete can be (floor ready it was described as) so more than ready for the build.
Initially the 2 sides and the back walls went up with each log being checked with a large carpenters square and spirit level - so everything seemed to be going fine until it came to adding the final 2 layers of logs and the 3 gable pieces.
I provided the supplier with photos of the pieces I still had left and then called (face time) him to ensure they would go up in the right sequence, and was when the fun started
2 of the gable ends didn't sit level and when they did it left a large gap between it and the log below....my fault apparently for not having a level concrete surface! (see later reference to log width)
The joints that the 3 supporting beams sit in where not cut square so although a nice fit on the outer edge, the inner edge has significant gaps.
Having watched the vidoes on their website on a number of occasions to ensure the bits went in as planned I found out that the windows they now provide do not have a groove in the bottom yet the log it sits on still has the tongue protruding..... so I had to trim to make the windows fit!
The best bit was when I came to fit the doors (double and single) - the door frame that fits into the gap in the logs was 183 cms in height ...the cut out gap left in the logs for the door measured....181cms! so the doors didn't fit. More chippying required.
Remember the gables not fitting, it transpires that the final log that supported the Gable end was 2 cms narrower on the left end than the right hand end..........that was about the gap that was left by the gable end not fitting correctly - so somewhere the measurements have lost 2 cms and this is all apparently my fault for not having a level base!. ..
To sum up the quality and accuracy of the finish of the parts supplied was very poor, the doors and windows have significant amounts of wood filler used on them to hid mismatched joints and the "cross" is the windows and doors are strips of wood forced in as on mine they are bowing to make them fit.
I did contact the supplier during the build and initially he was helpful in pointing out which logs go where but as more problems where encountered he did not respond to my email highlighting them.
I have had to pay out a significant amount of money to get the problems rectified by a joiner and given what this cabin cost I am very disappointed and annoyed that it is of such poor quality, even the window and door surrounds made to finish it off are made of cheap sawn timber!
The joiner used the term "rubbish" on a number of occasions as he was working.
I have had a couple of friends enquiry about the cabin supplier as they too are looking for a cabin but I could not and would not recommend this company to anybody.
The slick videos may look impressive but that bears no resemblance to the quality of the materials supplied for my log cabin.
Very very poor