My spinning sidebrush fell off. The retaining

\015 My spinning sidebrush fell off. The retaining screw was missing. On January 14, I ordered a package of 3 spinning brushes on and 3 screws. The package arrived today, January 22 with screws that are too small. The shipping cost me as much as the package, that could have been mailed and would have arrived much faster. How can I get the right size screws? Art Herzberg [email protected]\015 – iRobot Roomba 560 Robotic Vacuum