i believe this was talked about on here, im not sure if it was made or is possible to be made.
what the app would do is when you ignore a call. something will pop up asking if you want to send a text to that person. a simple yes or no. if you hit yes it will send them a customizable text that you wrote on the app ahead of time to use or a default one.
basically its a "im going to call you back" with half the effort
