Spreading wrong information for outstanding recovery

I availed a personal loan from a bank and have been paying EMIs on time till lockdown in Mar 2020. after that i opted for Moratorium and lost my job in between, due to which i could not pay my EMIs after moratorium for 3 months but i started paying it since Jan 2021 regularly. Though bank follow-up team is following for the outstanding EMI at once. I showed my incapability to pay the outstanding due to financial crunch. Although i had been in constant touch with them since last 10 days, they started calling other employees, (most of them i dont even know personally) in my office saying I have given their number as a reference. This they have done to 6-7 people and all of them called me and scolded me and humiliated why did i give their number to them as reference. They even misbehaved with the company reception female staff. They have jolted my professional as well as my personal image in office and harassed me calling more than 30-40 times every day. how can i raise a defamation case against them? please suggest. Thanks in advance.