DD is really hit or miss. I was lucky and didn't have any major issues. They did forget to write down my street number when they couriered the diffuser. Poor delivery man checked about 5 buildings before he finally gave up. Thankfully someone from bimmerkit called me the next day and they sorted out their mistake.
My FRP diffuser fit fine, but I have a friend who had some major fitment issues with his CF. However, they exchanged it in a timely manner. My read of DD is that they are extremely disorganized and not very detailed orientated. I don't think they are purposely trying to screw any of their customers. It seems like OP fell through the cracks, and I hope they sort the issue out quickly and compensate you in some way. Good luck.
E92 335i 6MT | Balloon White | Black Dakota Leather - Sold
PROcede Rev3 V5 | AE Quad Exhaust | BMW Performance Short Shift Kit | Gunmetal 19" M3 GTS Wheels | BF Goodrich g-Force T/A KDW 2 | AST 4100 Coilovers | Swift Springs F:280 R:560 | ER Charge Pipe | Tial Blue BOV | VRSF 3" Downpipes | VRSF 7" Intercooler