Thank you for response.
I haven't received any Workstation 15 licence and in MyVmware, when I choose "Upgrade a licence" it says "There are no products with license keys that can be upgraded" !
Did you get any kind of confirmation for the purchase. If yes, check the contact details, i.e. whether e.g. the email address, ... is correct.
In doubt, you may open a support case within MyVMware regarding this.