Mimik works by creating a conference call between you, the person you want to record, and our recording line, which records the call. To create the conference call, your mobile carrier MUST support 3-way conference calling. Without this, the 'merge calls' button will not work, and Mimik will not be able to record. Give your mobile carrier a call and ask them to enable 3-Way Conference Calling on your line. Once enabled, the 'merge calls' button will begin working as intended.