EBAY advice - possible cancelled transaction!!!

sigh........I am after some advice if someone knows, A buyer has bought an item of mine of Ebay, its coming up for 7 days, an invoice has been sent and I did send a nice email after day 4 just asking when payment will be made. No communication at all. I am still hoping they were only waiting for the 7th day and then pay....... but if not can I cancel this transaction, I dont want to go through the whole 'Unpaid Case' scenario and wait another 4 days before I can cancel, which after reading the rules on Ebay it looks like I have too. I'm not fazed about losing the fees, just want this cancelled. In fairness I will give them up till the 7 days ( which is in a few hours).
It has taught me to put a timeframe on payments for my auctions.
Thanks
SS

its a real pain in the butt when this happens, i had a fellow Ozcard member buy some cards from me on ebay and 2 months later he still had not paid, he started with a request for a list of all my souths cards and once he got it ......NOTHING..... then the auto matic dispute thing came in and it was then when i heard from him again but still no money
i have dealt with this guy before but never again and all he has acheived is this, unless i really am comfortable with who i am dealing with i will not allow that scenario happen again.
so i would just contact your buyer and if you get the BS i did then put the dispute because all those sort of people are doing is making ebay selling a real worry.