Update iOS 12.1 Iphone 6s still not available..

Hi everyone!

I have a serious question. I am struggeling already a long time with this. I can't download the iOS 12.1 update.. The iphone says 'update requested' and not going further than that.. but it is there already for a few months.. Also I tried by updating through Itunes.. Also no succes! Then it says I have not enough space on my laptop.. (but I am sure there is enough around 50 gb..) Also enough gb free on my iphone, still 70 gb! Can anyone help me what to try next?