When a buyer asks to cancel an order after purchasing it do I have to cancel the order

[paris.match]

I am so sick of buyers asking to cancel an order after they win an auction, Our when they select buy it now and then after they have done that they asked to cancel the order this has happened to me four times this week and it’s driving me nuts. Do I have to cancel the order when they requested it or can I not cancel it and then take out an unpaid case against them when they do not pay? Thank you in advance

[imastawka]

And it won't melt when it gets here - 14 deg atm   

[paris.match]

Awesome thanks