On purchasing any service on TagMango, you get added to the community of that particular service along with the creator and the other participants. You can access this community by downloading the 

TagMango app from the Playstore (Andorid) or the Appstore (iOS) and then logging in using your registered mobile number/email id. Your registered mobile number/email id is the same in which you received the OTP and the purchase confirmation.
       

Once logged in, you can go to the Messages section from the bottom tray and open the Mango Room for the particular service. You can text your creator there or you can go to the participants list and tap on your creator's profile to DM directly. 

Note: Messaging in the Mango Room or DMing the creator directly is available only if your creator allows it.