2015 TOYOTA 4RUNNER Wheels Problems

HAS A STEERING WHEEL SHIMMY BETWEEN 60-70 MPH, CAUSING PREMATURE WEAR ON TIRES. JUST BOUGHT 80K MILE WARRANTY TIRES ARE THEY ARE COMPLETELY BALD AT 20K MILES EVEN AFTER BEING ROTATED EVERY 5K MILES, BALANCES, AND ALIGNMENTS. UNABLE TO KEEP VEHICLE ALIGNED AND IN BALANCE NO MATTER HOW SOON I HAVE IT DONE AFTER JUST HAVING IT DONE (ONCE IN AUGUST AND THEN AGAIN IMMEDIATELY IN SEPTEMBER. BODY SHOP ADVISING THAT THE WELD ON THE REAR AXLE IS INCORRECT CAUSING THIS ISSUE. ATTEMPTED TO SPEAK WITH TOYOTA WARSAW, THEY AREN'T GETTING BACK TO ME AS THEY SAID THEY WOULD, CALLED CORPORATE 800 NUMBER AND SPOKE TO A RUDE FEMALE WHO WAS UNWILLING TO HELP ME. WAS TOLD THAT I HAD ALREADY BEEN DRIVING ON UNSAFE TREAD, THAT WHAT WOULD ANOTHER WEEK HURT? CAN'T BUY NEW TIRES UNTIL ISSUE IS FIXED BECAUSE THE TIRES WILL JUST PREMATURELY WEAR AGAIN.