Activation codes for new devices

Hi to all,

I have just purchased a new license and each time I access the new account from a new device, it asks for a code to be input for activation.  We do not have two factor set up yet.  Anyway, for the life of me I cannot access the email that has the code to activate on said device.  At one point, a support person said that the email for the account was on a bounce list, and was removed.  It worked one time, and then it stopped again, so people who are trying to activate on their devices cannot get it.   Any guidance out there?  So frustrated.  Many Thanks - Cherin