Depends how you worded it, if it could be read that you were willing to accept cash if it wasn't pick up or you mentioned anything about contacting you in connection with the cash then it could be seen as offering sale off ebay. If you said anything about refusing to accept Paypal for a pick up item and only accepting cash that would also be a hanging offense. It is unusual for ebay to suspend selling privileges completely for one transgression although they may ban you from selling for a few days or weeks so did you try listing the same way again without clearing it with T&S first?

If you are sure you did nothing wrong why don't you ring ebay and ask for a clearer explanation of the problem..