Would need a much clearer picture to really see the driver chip.
If your drivers are all used, and you're confident you've verified the issue is the driver, you have a few options.
If you're within 6 months of purchase from an authorised dealer, you may be eligible for warranty claim if you're sure you haven't done anything to cause the damage.
If not, warranty, you may be able to replace the driver chip if you're up to the soldering or have access to someone who can.
You could add a Duex2 or Duex5 expansion board and get more drivers and other sensor inputs.
You could use an external driver.
https://duet3d.dozuki.com/Wiki/Using_external_stepper_motor_drivers