Stop giving Medicare to foreigners of medicare age who have never paid one cent into it. Even if they became USA citizen

I work in the medical field and see foreign people who came to the USA . Most of these people are of Medicare age and can not speak English. After being in the USA for a certain amount of time they are eligible to collect Medicare benefits, even though they have not paid one cent into it. Medicare is to take care of USA born elderly. For every foreign person on tax payers Medicare, less money is available for USA citizens. There are USA Medicare recipients that have to decide whether to eat or pay for their medication. These Medicare people should not have to share money that they put into the Medicare program with people who never paid anything into it. I asked one person why they came to the USA. In very broken English I was told "I want USA to take care of me".