Well, you have a couple of things going on here. First of all, Dhgate is not a wholesaler. It is a website for on line sales much like Ebay. Therefore, if the boys were buying from there, it is possible they obtained some counterfeit merchandise. It would be a crime to intentionally sell counterfeit merchandise as the real thing.
The other thing is, the law firm appears to be legitimate. However, you may want to check with the CA Bar Association to see if they can reveal any complaints
against them or if they are in good standing. Anyone can send an "official" looking letter. So, I suggest you be cautious about responding to them or sending them any money. If they are scammers, contact from you will only give them more reason to continue correspondence.
There is no lawsuit, until the boys are served with a summons. If that happens, then I would suggest they consult with a local attorney who can help negotiate a settlement.
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