Hello I am a licensed attorney here to help you with your question, please review my response and do not hesitate to ask for clarification.
This is a common issues,
Under current law, as long as you have earned income, even after retirement, you continue to contribute to Social Security and Medicare with FICA taxes at the same rate as before you retired.
You cannot get away from these taxes even if you are using medicare and social security.
Do i get extra medicare benifits?
Not medicare, however your social security benefits can be increased,