I am assuming you bought a regular resin based system and not one of the highly questionable systems that supposedly softens by creating a magnetic field around your pipe. If you have the latter you were scammed. Resin systems do wear out over time as the resin eventually turns to mush. The resin can also get fouled by dirt and iron. So, if your system is over 10 yes old, may be time to replace it. I would suggest you get a water hardness test kit from a big box store and see if your water is hard.
Sounds like calcium. if you purchased a unit from affordable water and provided your water's hardness, affordable water would have programmed the unit to proper specifications, like they did for me. Look up your city's water hardness. Then check your unit to see if is softening at the proper levels.
Thanks! Your answer is awaiting moderation.