Three systems, three versions of the same customer
The same customer exists three times in your stack. One record in the DMS, one in the CRM, one in a spreadsheet from a campaign two years ago. Different phone numbers, a misspelled name, a trade you no longer know about. When a tool tries to act on that, it acts on the wrong version, or it gives up.
Identity resolution
Most data problems are resolution problems. More records will not fix a customer who exists three times.
The records you already have need to agree on who the customer is.