You can write to support@freshsales.io to check whether both the products are in V2. If not we will send in a request to migrate your account to Org.V2. If both the products are in different pods,  say Freshdesk is under EUC pod and Freshsales is under US pod, the new Org cannot be linked to the existing Org. Please write to support@freshsales.io to have both the products in the same pod.