Laptopgallery.in — Cancellation of order

I ordered for Aser aspire5755g original battery on COD basis.They called me and informed that they are packing it and sending within 4 days
I requested them on same call to mail me it's. Invoice copy and date of delivery
But they didn't send me Invoice copy in advance hence I requested to cancellation my order, Then they immediately sent me message that your package is shipped