Dear Sir, please see my reputation to make your decision.
It is possible in the recent OS alright, but the limitation is, you have to keep the app (which we will create) running as "minimized" condition. The app will be auto-minimized in task-bar. When a call will come, it will come into action and when you take the phone near your ear, it will make the call receive. Then it will be active to detect shake and when shaken, it will hang the call.
Sir, I know I have posted amount which is beyond your budget. But, I have already created this feature in a large project, so, you can rest assured you are going to work with an expert. After all, expertise has its own cost, sir.