Help to find the brand single handle bath tub and shower faucet

Can any one of the expert here can help me identify the faucet in the attached picture?
The house is 9 years old. The faucet is not mixing the cold and hot water. Either it works in fully hot or fully cold water region.

WE need a photo of what's behind the plate, since that handle is too generic to help us. It looks like a Delta, but they usually have their name on the plate, but could be one of the innumerable "knockoffs", which use the same parts. That type of valve, when it goes bad, usually gives ONLY hot or cold, not both but no mixing, (which given how the operate seems almost impossible to occur).