How can I recover my lended money from my mother who married to another person?

Sir/Madam, I belong to a small village Disket Nubra Leh district Union territory of ladakh. I serve in the Indian Army and I am in a relationship with a girl who belongs to another religion but religion isn't my problem my mother who got divorced with my father long time before got married to another person is opposing my relationship with the girl because of her caste that's why she isn't returning my money which I gave to her amounting around 13 lakhs of which she only returned a car worth 450000 and a cash amounting 1 lakh now when she got to know about the relationship she never returned the remaining amount of 750000. I always appreciated my mother and after joining the Indian Army I always kept my debit card for around 4 years and I don't know how much money she debited my money from my debit card and I want to change my religion because I find no support from my family members except my father who is suppressed by the society and religious community they want to take my life I don't know. Now I am on a holiday far from my native place.