@Rafiullah Karim I wanted to provide a follow up given that we had an opportunity to speak offline. For those who might be following this thread, we learned that duplicate contacts are being created because the Unified CRM extension was not configured properly to find contacts successfully in Clio. So each time the extension would fail to find a contact, and prompt @Rafiullah Karim to create yet another contact.
Once I pointed @Rafiullah Karim towards our documentation to make the contact lookup process work successfully in Clio, duplicate contacts were no longer being created.
Best practice for Clio users: the key here is using a consistent phone number format within Clio. When phone numbers use divergent formats, then the software has to conduct multiple searches for phone numbers which slows the contact matching process down considerable. This is a limitation with the Clio API which we have communicated to Clio on multiple occasions. The Clio team has been reluctant to commit to a fix. We continue to look for solutions to alleviate this problem however, and will update the community if we come up with anything.