laguna 3 dpf problem

hi, i hope someone can help me, i recently purchased a luguna 3 2.0 dci, for the first 4 weeks was great, loved it, but then one day the "check injection" warning light came on & the car went in to restricted performance mode, i took the car to the garage & they told me it was the dreaded dpf system, having experienced this before with a mazda i was gutted, i can't afford to buy a brand new oe dpf system, so does anyone know of any renault spares, that may stock an unblocked second hand system as the renault garage said that an aftermarket one won't work due to the ecu not being able to recognise it (i had the same problem with mazda), really hoping someone can help.