Hi,
I can help you with this but please keep in mind issues with Gmail take at least a couple of weeks to get better.
What I can do for you is as follows:
Check your domain for the right authentications. SPF, DKIM etc
Check your sending IP for any blacklists
Help you setup Google Postmasters so you can see your domain and IP reputation
Review your template to see if it’s an issue with your code
Make suggestions for managing your data. This is key, if users mark your email as junk or just don’t open it Google will start sending you to spam
Please note, no one including me can guarantee inbox delivery to Gmail. If anyone tells you they can then they are lying.
I spent 5 years working for a competitor to Get Response and dealt with these issues everyday.
Please let me know, based on the above if you want to work with me on this. Again, I cannot guarantee I can deliver your emails to the inbox.
Kind regards,
Bilal