At one time Home Depot was advertising a life time guar. on the T1-11... You need to check back with the contractor. I installed T1-11 on my mobil home and now I have to replace it also. If you put T1-11 back up, you need to prime it with oil base primer, on both sides. Do not let the weather get to it first.

T1-11 is a the patern of the siding, not a brand.

Orginally it was a spec for a type of plywood siding with vertical groves (avaialbe in several different spacings, but 8" oc is most common).

But now there are many different types of siding made in t1-11 paterns.

Plywood, fiber cement, and even vinyl.

But I suspect that yours is a type of hardboard or composite material.

In many case the back of the panels have the manufactures brand and lot numbers. Somes you can tell from the paterns if it has wood grain "finish".

Most of the class action that I have seen on hardboard siding has been for lap siding, but there might be one for panel siding.

Sart googling "hardboard siding class action".

Then you might try adding t1-11 or panels to that search string.

If it is the plywood type of T1-11 you do not want to apply an oil based primer to it as the solvents attack the glue and cause it to delaminate an dthat is why alot of it falls apart over time. If you go with an all acrylic system I have seen it last many years without any problems.