How to pick correct front derailleur replacement
I would suggest you return the bike to Walmart. If the derailleur doesn't move it is not a spring that is too tight. There is something either out of adjustment or broken. The problem with buying a bike at Walmart or other department stores is the skill of the person assembling the bike varies from competent to no idea what they are doing. The bikes they sell are at the lowest possible point. They generally don't work well right out of the box. If you replace the derailleur yourself you have potentially voided the warranty for any other issues that show up.