Personal loan

I have a personal loan with hdfc bank. Due to some reason my emi for this month was bounced. I got a call from collection team 1 day only once and was not able to pick up the call. Then they gave a call to my friend for whom i gave refrence at the time of taking loan. They called him 4 to 5 times and took my brother's number and called him 4 to 5 times. This happened for 2 days continues even on sunday. They only gave calls early morning and after 1pm they didn't gave the call. On monday they again call on my brothers number saying that my phone was not reachable. I informed them i would be paying emi in 2 days. Again they gave 4 to 5 calls on tuesday early morning around 8am to my number and my brothers number. I have taken the loan and they are calling my friends and family to recover the loan. As per law are they allow to call my friends and family to recover emi? I have already written a mail to there greviance redressal team but i dont think they will take any strict action against the collection team. Can i file file a case or complaint against bank collection team as they are calling my friend and family member?