Here what I think could have happened: You had a malware on your computer, which allowed a hacker to get access over your account and steal your coins by doing a fake trade with himself.
If that's the case, Localbitcoins can't do anything since Bitcoin transactions are irreversible. Which means that your coins are probably gone.
I do care more of my account's security then I do for myself, I do daily scans, download and run files on vps , use hard to break passwords , two step authenticators so hacking is not an option , someone told me that it is not deducted but it is "reserved" and released once both sides accept the trade, so let's see , waiting for hours now , payment window was around 5 hours so it should close soon or ...