ios 13.1 update

so i updated my phone the other day using iTunes as i have no storage on my phone for the update. i still had to delete loads of apps. the update completely wiped my phone and wouldn't update or restore for 3 and a half hours. my phone hasn't worked properly ever since. i now have to update to 13.1 and I'm using iTunes again, I've deleted everything i can but its still saying i have no storage on my phone. the update requires 1.3gb, however on my iTunes (on my laptop) it says i have 6.13gb free. people say to use iTunes if u have no storage so why is mine still saying i have no space when i clearly do?