VKB North America only supports VKBsim® products purchased at VKBcontrollers.com (as evidenced by the VKB North America sales record, invoice, and order number).
If you’ve purchased a VKBsim® product from a third-party reseller (e.g. Amazon, X-plane.org, Dix30 Simulations, Aliexpress, etc), please realize these resellers operate their own independent businesses and customer support channels. These resellers have distribution/wholesale agreements with VKB HQ in China, and such agreements are unrelated to the operations of VKB North America via VKBcontrollers.com.
Therefore, purchases from any third-party reseller are not supported by VKB North America via VKBcontrollers.com, and any support or warranty requests for VKBsim® products bought from a third-party reseller will have to be submitted to (and fielded by) the same third-party retailer you purchased from and who issued the sales invoice to you.