Resignation and relieving letter

Hi sir/madam, I have joined a company in the year 2019 November. I also signed a bond for 3 years for which they promised us to provide the proper salary as given in the joining letter. They mentioned in the joining letter that for the initial 3 months my salary would be given as 15,000/- , after 3 months my salary would be hiked to 20,000/-. After joining the company they didn't increase the salary after 3 months and I was getting only 15,000/- till the month of May. From June 2020 my salary is still reduced to 4,600/-. The company even promised us for getting a clinet after 3 months of joining, that never happened till now. Now I wanted to leave the company they are not accepting my resignation and not willing to give relieving letter, they are asking me to pay 5 lakhs bond breakage amount as I have signed in the bond. If the company has not followed any bond rules how can they ask me to pay as per the bond? Please help me for getting relieving letter without paying bond amount.