Bikes ALWAYS need a bit of minor tuning post assembly. Wobbling wheels are another matter and without more info I won’t speculate.
I would return the bike and explain your feelings of having “rushed” the assembly. For good measure (and good will) I would be sure to include something along the lines of a complimentary “I’m sure this example doesn’t reflect your true abilities,” and then be patient while they get it right.
If they don’t (or can’t) get it right after that, you might want to look for other options.