Credit card: Closing your account

I sent a written request for debt validation to Midland Credit Management ( regarding account # XXXX ) on XX/XX/year>, which was delivered and confirmed via XXXX tracking. As of XX/XX/year>, I have not received any validation of the debt, yet the company has continued to send collection letters and has not corrected or ceased collection activity. This violates my rights under the Fair Debt Collection Practices Act. I request that the CFPB investigate this matter and that Midland cease collection activities until proper validation is provided. Amount : {$1400.00}