The best thing you can is call redcat on monday and explain everything that has happened in a nice way; I know you are frustrated right and it is understanding but if you call them up demanding and threatening them it will only make matters worse and will get you no where.
Believe me I know from experience; just be nice I am pretty sure they will work with with you.
Obviously it is an issue with the rx an the tx; I am pretty sure they will replace whatever needs to be replaced for free.
Just tell them you want send the car in have them look at it; tell them to pay for the shipping costs.
That's what I would do.