Does the charging port have anything to do with the motherboard on a laptop?

about 2 years ago we took my gateway laptop which was worth around 699 usd in for not being able to charge. they said that it was the motherboard and that it would never turn on again unless it was replaced. and they were going to charge 769 for the repairs. We said no and we would just buy a new computer. so today i took that very same laptop and exchanged the dead battery inside for a fully charged one, but it still did not charge, but it turned on for the first time in 3 years. So either they were lieing to us about the damages to make a big profit for doing nothing or they didnt even look at the laptop. i was using geek squad from best buy. repairs for this would only cost around 10 dollars i found out.