Canada does not have a free healthcare system.
There are 10 provinces each of which operates its own health insurance. They also charge premiums to citizens and those premiums are mandatory in most provinces. NOT free.
The largest province has 14 million people. This means that these insurance plans have so far avoided the worst problems of scale such as the NHS problems in the UK where there are 66 million people.
Corruption is a problem of scale. The larger the organization, the worse the corruption problems and the greater the need for OVERSIGHT. For instance, who oversees police corruption in the USA? The 2nd ammendment lets every citizen take charge of their own safety. No need to wait for a corrupt police officer to arrive.
This is the secret of Trump's health care plan. There will be MANY independent insurance providers, the citizen can choose to move plans whenever they want to, thus providing citizen oversight of health insurance. This will prevent Communist monopoly centralization which breeds corruption.