I just reread this entire thread twice and see a lot of confusing info on what the OP should do, by those who have different units with different carbs. This doesn’t help the OP resolve his problem. Now that we finally know which engine and carb he has, I would recommend the following. Seeing that the unit was purchased online, through a Big Box store website, I would contact their brick and mortar store with all information of how you have try to resolve the problem. Make sure you have all paper work with you, DOP, unit model and serial numbers, engine numbers, repair work order. If they refuse to work with you, you will have to contact corporate through the website. I understand that this is going to take you some work and time to resolve, which again supports my ongoing recommendation to always buy from a dealership.
That all said, I’ve got a problem with the dealer you took it to for service. According to the model number this engine does have a choke, so the tech you spoke to is any idiot and is blowing you off. Second, if it was a bad fuel problem they should have saved some of the fuel to show you what they found. I’ve worked at dealerships since the early 80’s and these type of fools give all dealerships a bad rap. I will agree that these plastic carbs can be a real pain in the butt, especially for inexperienced techs, which is why I see many of them blaming the problem on bad fuel.