I was offered a Job offer to work with my employer for 3 years. My employer opted to file my H1B Visa and bear the expenses. My employer also stated that if I leave the Job before 3 years of employment then I will have to pay my employer $5200 for the H1B fees including attorney fees and Training fee.

I left my employer within 18 months of employment because of the unfavorable working conditions at my workplace. My employer demanded $5200 for breaching the contract. I informed my employer that H1B fees are required to be paid by the employer and not the employee. My employer asked me to pay $3200 as the recoverable expenses and I paid $3200.
Was it legal for my employer to ask for $3200 and if it was not legal, is there any way I can recover the expenses back from my employer.