I normally buy OEM products from IoS. I've had problems with aftermarket products/clones. One time, I have to replace the alternator 3 times until I got a working one. It has limited lifetime warranty but doing it 3 times was no fun.Going back to your problem, remove the starter and take it to AutoZone or the likes for testing. You can also do it by using your car battery to test the starter solenoid and the starter itself. You will need several test clips, DVM and secure the starter so it doesn't move during testing.
To test the starter solenoid, connect the Positive battery terminal to the starter solenoid connector (single-wire connector) and the Negative terminal to the starter frame. The starter solenoid should energize and the starter shaft should extend (engage). If you have an ohmmeter, verify that the starter solenoid contacts are closed (2 terminal studs at the back of solenoid).
ENSURE STARTER ASSEMBLY IS SECURED BEFORE TESTING IT. To test the starter solenoid and the starter motor itself, connect the Positive battery terminal to the starter solenoid (single-wire connector) and starter battery input terminal (free stud behind solenoid) and the Negative battery terminal to the starter chassis. The starter shaft should extend and then spin. If not, you may have an electro-mechanical problem within the starter.
If you are bold enough, you can dis-assemble the starter. Just make sure you put alignment marks so you know how to put them back together. It possible the starter solenoid plunger is bad; the starter motor planetary gear lube is dirty or dried up (can be lubricated with white lithium grease); starter motor rotor-stator are gummed up (use contact cleaner to clean).
