Ok. let's put this to bed.
Some people try to register with as little information as possible, not trusting us with their info, like a name, but expecting us to trust them, not knowing them from Dick or Harry, to post on the forum. Blatant use of proxies are always denied any access so the registration is rejected. Most common reasons for rejection are :
Username Fred Blogs
Name Fred Blogs
IP address = Karachi Pakistan.
Then if the registration looks genuine admin accept the user and they become a registered user, with limited funtionality. The block on sending PMs is due to the potential of sellers, undesirables, or terrorists etc. using PMs to communicate, or spam, without ever needing to post or be active on the forum, and until they have posted and introduced themselves we don't know they are genuine.
There is no automatic way of unlocking Registered User+ as admin wants to positively vet those wishing to use PMs It is generally a limit of 10 posts but there is no guarantee, or right, for this to be granted.
Hope that explains the situation.
If anyone has not been raised to registered user +, and thinks they should have been, they need to use the contact link at the bottom of every page to send an email.