That is not true... There are several accounts on this forum where people who took the test from the link without the e-mail and their test was marked complete. On the contrary, I haven't read anything on this forum where people who did not get the test e-mail being asked to take the test againYes, I actually looked that up.
Although, apparently the people who took the test from the test page directly were asked to take the test again.
So, not sure what to do.
If you are that worried, call IRCC