Existing customer paid $124 for high-speed internet service far beyond what it's needed

I just found out that my xfinity plan is Gigabit Extra Internet which is far beyond what my family needs. And I have paid over $100 each month for years. 

I see xfinity is currently offering 300Mbps for $40/month  to new customers in my area with a five year price guarantee. I'd like to stay with Xfinity and I'm hoping someone can review my account for any loyalty, retention or existing-customer offers that may be available. 

Thank you.