terms an conditions

A friend of mine, from Punjab runs an authorised franchise of apparel store in Amritsar. On my visit to his store, he requested me if I can help him locate any places to buy original/duplicate fashion apparel in my city i.e. Delhi. As his authorised distributor purchase products from Delhi and use to charge heavy amount on the same from him. I found a couple of vendors who sell the products he required, and I started helping my friend by purchasing things from delhi and he use to pay me through cash transfer in my bank account. Am not a professional buyer/nor a businessman. Though no terms and conditions were signed, no commission or percentage was set among us. I use to charge only patrol fair i.e. 200-300 rupees. And he was happy with this system as he was saving and making huge money out of it. Now after he has purchased products in instalments (6 months) worth 9.5 lakhs and paid 9.3 lakhs to me, he is complaining as some (10%) of the products are not as he asked for though he’s forcing me to get it returned and asking me to pay his money back. I am no where in a condition to pay him anything as I don’t have any source to sell them or return them because there was no refund policy between me and him nor with the vendor I purchased from. All these deals were done on mobile messages through “whatsaap” between me, him and other vendors. All the money transferred to me was through cash deposits in my bank. No invoice/quotes were provided or signed. I have not charged any commission on the products, but he’s forcing me to pay him. What shall I do?