Crushing is when a face yarn fails to maintain its retention while matting is when the fibers fuzz and entangles so that the yarns appear as one.
Your face yarn is an important issue in determining why your yarn is crushing. There is a warranty covering your problem but for it to be covered, an installation that meets Carpet and Rug Institute standards will be necessary.
If your carpet meets minimum installation standards, then Laboratory testing will normally be required for a manufacturer to honor a warranty.
OLEFIN is the most crushable yarn there is. If you have olefin, you may still be in luck, because there are warranties covering crushing. Although, laboratory testing will be necessary to verify if the yarn fails to meet a minimum standard.
POLYESTER is the second most crushable fiber. However, you may have a warranty that could be honored if your installation is good and the fiber should have failed to meet the standards set in testing.
NYLON is the most resilient synthetic fiber there is and has not had a warranty for crushing until its sixth generation. Like olefin and polyester, your installation needs to be good and the fiber should have failed to meet the standards set in testing. If your yarn is nylon there is a stronger chance that you are suffering from a soapy residue problem and a problem in the installation .
WOOL is the most resilient fiber there is, however, we still hear of problems with crushing. If wool is your fiber chances are you have a latex problem .
Number eight of the CRI CLAIMS MANUAL says this:"Pile crushing, pile shading, and soiling are not manufacturing defects and will not be considered as a basis for claims. Claims for fuzzing and pilling will be subjected to examination and testing by the manufacturer. Claims for missing tufts will not be considered except on a basis of repair. No claims will be honored for carpet installed on stairs, in elevators and in bathrooms. The mill reserves the right to correct any repairable manufacturing defect. (See Glossary for definition of terms)."