Not a lawyer but did study to be one before coming to my senses. The letter has too many holes to be of concern. The simplest answer is you bought what you thought we homage watches in the style. Most of the DHgate sellers blur or hide the dials so even if investigated, they would have to prove you intended to buy trademarked branded kit. It would be difficult to prove in court and cost a fortune. These are simple posturing steps to discourage people.
Frame it above you watch box and enjoy.