Young guy in my neighborhood started a balloon delivery biz. Simple and dumb as it sounds.
Tell him how many you want and what colors and such, he brings them to your house at the prescribed time.
They are big high quality balloons with nice ribbons. He has the little weights if you need them and knows how to affix them to whatever you need.
He would text a link with the colors and also had a sample book he would come by with so you could choose. He started with kids birthdays, graduations and such delivering maybe 5-10 balloons at a time. Eventually he was doing events as well where he would do the balloon arches and that “higher end” kind of stuff.
He started in high school and did it through college. All word of mouth, no real marketing at all. It was a nice little side hustle for him.
The key I think for him was that he was extremely nice and personable, dressed nicely, was very punctual and always 100% of the time “made it right” for his customers.
Hire a new one, what other answer are you expecting?