*NEED HELP* With this theme pitch stylesheet missing after buying premium

Hi, Right so I installed pitch theme and liked it so i decided to upgrade it to premium, so i brought it then i entered the code they gave me i put that in then it downloaded the theme then when i went and tried to update the theme to get the premium package, i just kept getting Briefly unavailable for scheduled maintenance, so after sorting that out a couple of times, i decided to try and update the theme again and this time i got a fatal error php and my site just went blank and the theme said style sheet missing so i can’t uninstall it our nothing

Need some serious help please