i want to know if the potentiometer is broken or just dirty and if it's broken can i find the same in the market?
Given the low cost of these products, they use the cheapest parts that fit and those are hard to find.  The wiper is unlikely to be gold plated so oxidation can occur then gets cleaned by friction. Excess friction removes the metalized  layer on the plastic film, assuming most likely cheap, metal film pots.
They suffer from frequent use , dust and corrosion.  Better quality pots are cermet.  Wire wound are more expensive low R values and unlikely to be used there, and carbon film also exist.
If spray or pouring alcohol electrical cleaner doesn't work , replace it with fixed R's and forget it. Using common Isoprop. has some residue that may work or not.
If you are persistent, you can find one of a similar value and wire it up so it works with some persuasion and creativity.  How creative are your searches and how much is it worth?  Value Village sells these systems for about $10.