Xfinity Promotional Discount Ending - What are options?

I currently have a 2 year contract for my current plan, which has a substantial promotional discount for the 2 years. The discount is ending at the end of march, that is causing my bill to double. Any promotions available to keep me at the same amount? I've been a diamond customer and 15 + years with Xfinity. I know AT&T fiber is available as well, but being a long time customer it has been reliable for services.