We are very sorry to hear that your backsplash was bowed and apologize for the effort you took in an attempt to straighten it. While caulk may help and we understand your wish to move forward, a new backsplash may give a much better result. The team at your nearest Home Depot, or if purchased online, Home Depot’s Customer Service at (800) 466-3337, can assist you with a return and reorder per their Return Policy. We want you to be able to enjoy your completed project with no regrets. That is our wish, and again, we are sorry for this disappointment.