Lizzo's Postmates Driver says she's Not a Food Thief and now she's scared

Postmates delivery driver Lizzo openly accused of food theft says her days have been the worst of her lives ever since— she's humiliated, frightened, and worst of all... It's a gigantic rap.

Tiffany W., the driver, is telling TMZ... Her world turned upside down when the "Truth Hurts" singer excoriated her on Twitter— to her nearly a million supporters— stating, "This girl Tiffany W. stole my food, luckily I'm not fighting anymore." Lizzo also included a screenshot of her profile photograph.

As for the delivery incident ... we're told Lizzo's order was supposed to go to a Boston hotel, but there was no room number listed and no one answered the phone linked to the account.

it was seafood, which Tiffany doesn't even eat.

Postmates spokesperson tells us ... "As soon as Lizzo reached out, we looked into the matter and quickly resolved the issue. We apologize to Lizzo for any inconvenience." However, we're told the company determined Tiffany waited at least the required 5 minutes and wasn't able to reach the customer, so she moved on like she's supposed to do.

Lizzo's since deleted her original tweet putting Tiffany on blast and issued an apology ... but it seems like it might be too little, too late.