False commitment made by company

Hello sir During the interview, HR committed to us that we will get 24k after completion of 6 months and for that there would be a deduction of 2000 rs per month as a caution deposit for the first 6 months only. They will deduct 12000 in 6 months and after 6 months they will give us 24000 but they gave only 12000(In offer letter its mentioned that we will get a monetary bonus from the company) now in 7th month also they have deducted 2000 rs from our salary but it was mentioned in the offer letter that the deduction will be for first 6 months only so can we file a case against the company asking them to return the money? Thanks in advance Vinit