Well if the company is gone then go direct through Dynavin or one of their listed distributors. If the company is around, make them warranty it through whatever laws your country has. (ex. here we have a Small Claims Court).
before doing this make sure again it's that particular unit and not just something being installed wrong.
OE CSL WHEELS - OE CSL BRAKES - OE AUTOFLD MIRRORS - CSL TRUNK - CSL DIFFUSER - AA TUNE - AA PULLEYS - AS 40% SSK - BILSTEIN PSS9s
CF CSL LIP - NAVI - BMWPERF CF STRUT BAR - BMW GROUP N MNTS - GRUPPE M CF INTAKE - SUPERSPRINT - UUC BRKLINES, TRANS, RTABs - H&R SWAYS - 4.10 M-SPORT DIFF