I keep getting this message,but I have no messages in my inbox. What am I supposed to do,I can't delete what is not there?

?? I've tried a couple of times to PM you and thats what it says

Did you use the pull down tab on the "show messeges from" box? It's default is "last 10 days" but there may be some older messeges in there. Use the tab abnd select "from the beginning" and see if that clears the box

You have to clear out all of your messages, in your sent items too. These all go against your allotment.