Boom 125cc not starting

[Hirales]

hello i just bought a new boom 125cc from red fox motorsports and I've had issues from the moment I got it but the biggest one being is the bike wont stay started it will start then die then its a bitch to get it started again im hoping someone has some insight on this and would be able to help me figure out what is going on ive tried calling the place where I bought it but its like pulling teeth for them to answer and when they do they either hang up on me or say they don't know anything altho they are sending out a battery because the original one had a dead cell in it but I changed that out and it still does the same thing if someone has been through what I'm going through and can help me it would be much appreciated thank you