When I insert the USB stick into the PC it tells me it is write protected, I tried to run chkdsk but it gives me the error "Windows cannot perform disk check on this volume because it is write protected". Same thing by running diskpart. The USB stick is 32GB but selecting all the files tells me that 327GB are occupied. How is it possibleBrowsing I found these folders with these strange characters (see the image) how did this happen?
The USB stick itself are most probably corrupted. Then it also probably affects the file table, making you observing erroneous size counts.
You can try to gamble that it's just the file table that are corrupted without a failure of the usb stick itself (pretty unlikely), and you can flash another USB stick (that you're not using) with Gparted tool. Boot your computer using this usb stick with Gparted, then use the tool to rewrite the partition table (select msdos type) and from there try to create a new partition.
Just don't trust the USB stick any more, because any data you store on it may be lost at any moment (if the Gparted actually sucessfully making a new partition table and a new partition)