Chargeback Prevention

Hello! my name is Paul. I work for a Merchant outsourcing company

I have to manage multiple merchant accounts for clients from all over the world . I also look after Merchant Chargeback Assurance.
I am facing multiple Friendly Fraud cases for my merchants accounts.
Recently I got a call from ChargebackExpertz saying all my merchant accounts will be closed if I receive any more chargebacks. I called the banks and they also confirmed this.How can These accounts get so many chargeback in so little time
I am confused because all the chargebacks that I have received seem to be false as the product was delivered on time.I suspect a rival company's hand in this act .Because our site seems to be selling more. I am confused
Please help . I don't know what to do.Any suggestion will be helpful.
thank you.