Our support team will need access to your Google Merchant Center. Here is how you can grant access to your Google Merchant Center account to our support team.
Follow step by step process given in the screenshots: 
1 - Click on 3 dots (menu icon) in the top right corner. 
2 - Click on Users from the drop-down menu. (See next screenshot)

3 - Click on "+" icon here. 

4 - Put in the Email address provided by Support Team, or if none is provided, kindly grant us access to support@simprosys.com

5 - Click on Add User after entering the email address. 

6 - Make sure you "Check" permission with "Admin rights". We ask for admin rights because, once the purpose of access served, we can remove ourselves. And then Save. 

Here is a quick link to install the app: https://apps.shopify.com/google-shopping-feed
For any further query, feel free to connect with us at support@simprosys.com