I have a 12 year old Tennis Tutor Ball Machine that still works very well, although it has gone through several batteries & many cleanings. However, the balls now jam regularly because 2 of the "spring (arm?) thingies" that help control the ball feed are rusty and bent. Is there a replacement part, or a suitable substitute part I can use? IMHO - this machine should be in the "Ball Machine Hall of Fame". Thanks for any help.