Getting charged for carpet

[Arthur Cecchini]

Hey all,

Being a landlord previously before willing the properties I have a question. 

My wife and I had to live in a place out of town for a year and we rented from a big box company in the local area. Everything was smooth until move out. The company is attempting to charge us for new carpet in one room and the landing. For start I took around 900 pictures of the property prior to move out and the inspection went well with just a charge for a broken blind. 

Come to find out the landlords pull back the carpet and are attempting to charge for replacement due to some discoloration/possible stains noticeable only on the backside (stitching) of said carpet. One room has two and the hallway only has discoloration. The padding underneath is in pristine condition, the sub flooring I could not view since it would damage the padding pulling it up, and the pile of the carpet are all brand new looking besides minimal wear and tear. Of all this I have pictures to verify.  I am not sure where the stains came from (maybe a cat barfed?) but nontheless there was no odor to any stains or any damage to pile/padding. They were maybe a few inches in diameter. 

Long story short can they actually attempt to collect the entire replacement for carpet (TN) without depreciating (one year on this carpet) or attempting to “clean” the stitching first? Nontheless I have no way of telling if this was due to a stain out on carpet prior to its installation or honestly after I moved out (I find it fishy there was no abnormality noted on the pad or the pile) I went thru the pile w regular light and UV light as I did previously in my rental since it tells the whole story and found no abnormalities prior to or after steaming the carpet. Again I could not pinpoint what may or may not needed pretreatment since obviously tenants cannot tear up the carpet themselves but I could only view it after. 

To me the carpet is odorless. Appears new (as does the rest of the unit) and replacement of the carpet is unwarranted and I am mostly asking if a landlord in TN can charge only for a stain on underside of carpet with no damage to pile or padding

Thanks in advance. I feel like if I would have done this to a prior tenant I would have lost in small claims for dishonest use of deposit and failure to act in a stepwise fashion (replace one section/attempt to clean first. 

This company is well known in the area for attempting to replace carpet after every tenant for anything they might think abnormal even if it is basically just wear and tear.