Upgrading will probably help, they are probably trying to pay with a credit card and you are on a free account which comes with limited support for CC payments and what cards you can be paid with, 5 CC transactions I believe is/was the norm. In my opinion you might be better off to accept bank wires as you can't be **bleep** over should a dispute arise. I guess it would depend on how much the payments are for and if your clients are legit businesses with business accounts.
