I had 10 year old Nitto Terra Grapplers which didn't look that cracked up but had to go due to age. Look of your 4year old Wildpeaks is concerning. I'd call Falken execs and ask for new replacement. Be firm and tell them you feel unsafe driving on those. That usually gets their attention. At worst - they will give you generous credit for new set, but most likely they will cover your new set entirely. If you work with Discount Tires, they are pretty good at calling this up to manufacturer for you. If not here you go:
Falken Tire Corporation Headquarters & Corporate Office
Falken Tire Corporation phone 800-723-2553. Falken Tire Corporation Headquarters Address is at 8656 Haven Ave., Rancho Cucamonga, CA, United States, 91730.