Hi
I have worked on many integration between Infusionsoft and third party payment gateways. For example, Infusionsoft and Stripe, INfusionsoft and PayU , Infusinsoft and Gingr etc to name a few.
If you search for Infusionsoft in Freelancer, you would get my Profile at the top. I am confident, I can complete your project in 2-3 days.
Let me know, if you are interested and I can start right away.
Thanks