Visitor visa extension

[wallbr]

So my parents recieved a medical request for their visitor extension today.
But they will be leaving Canada in 3 days. What should I do? Should I contact immigration to inform that they wont be able to do the medical test? Because if they don’t do it in 30 days the application will be refused. And my concern is: if the application gets refused because of that, the additional time that they stayed here with implied status with the extension will be considered ilegal?
Thank you

 

[Joshemir]

^ up!