Toner refill leaving magenta smudges and spill

[suneet]

I recently refilled the magenta toner cartridge in my Brother HL 3040 CN printer. I bought the cartridge off ebay. I have had similar refills previously without problems. However, there is extensive powder spillage inside the printer everytime I use it alongwith extensive smudges on printed paper. What is the likely problem and how to fix it? Thanks