Claims not paid from maternity benefit

We recently found out my partner is pregnant and subsequently went to the gynecologist to confirm the pregnancy. During this visit he sent us to the lab for the pregnancy blood work that needs to be done, which we did. A few days later we learned that Discovery has a maternity benefit and we activated it. At this point the blood work for the pregnancy tried to go off our MSA but failed due to insufficient funds and subsequently I have to pay it. I resubmitted the original claim and asked Discovery to claim from our activated maternity benefit, only to be told because the benefit was not active at the point of the tests I cannot claim and have to pay the amount myself and in addition because the tests were done in December I cannot claim from the 2018 benefit.

Now answer me this, how should I have activated the benefit before the tests were done, if the pregnancy was not even yet confirmed and is there no 3 months period on submitting a claim?