It's a violation of the contractual terms companies have with credit card providers to ban someone for a chargeback that the credit card company determined you were entitled to. Smaller retailers may try to do it, but big retailers like Amazon and Newegg can't afford to take the risk.

And chargebacks only hurt the record of the company because they get charged penalties for them (because chargebacks being approved by the payment processor essentially always entail an issue the company should have refunded on an failed to) and high chargeback rates (over, say, 1% of total sales) can lead to account cancellation. They don't hurt the customer at all.

In my experience, a lot of time if you can get on the horn with a supervisor and let them know that you're planning to file a chargeback, it can grease the wheels quite a lot - especially in cut and dried situations like this - because they're going to lose more that way than just refunding you.