Discovery's ********* clauses and refusing to do payouts

Good day.

I have been struggling with a Discovery group risk claim for 2 years now.... Their clause that says "In the case of disability and severe illness, Discovery Life will not pay a claim during the first twelve months of the life assured becoming a member if, in the opinion of Discovery Life, the claim is directly or indirectly attributable to an injury or illness for which the member sought medical advice for or knew about (or could reasonably be expected to have known about) during the six months before joining the scheme.

Now i was Never diagnosed with any condition prior but i was given meds for possiable relief of heartburn etc.... Later on i was diagnosed with a hernia and had x2 surgery for it . I then had a perforated Gastric Ulcer that lead to septecimia and now Discovery is saying if i never had a hernia operations i would of never gotten septacimia which was an indirect lation to a sequence of unfortunate events. HOW CAN THEY BE SO *********?????