Disappointed in Bravecto

Very disappointed. Have been using bravecto for my dogs for years now. Bought my dog the chewable tablet on 14th of September and yesterday he started getting sick and today(8 December) he was diagnosed with Bi****y. It has not been 12 weeks yet and my dog is covered with ticks. Also bi****y fever is caused by ticks and has a 12 day incubation period so which means my dog had ticks biting him and making him sick almost 2 weeks ago.!!!! I have proof of all this because i bought the bravecto from my local vet. Now i have a huge vet bill and when i called MDS they basically told me it is still possible for a dog to get bi****y even if he is being given bravecto?? I told them about my dog being covered in tick and they said maybe he got into a tick nest... i am disappointed that they didnt even offer to give my dog a free bravecto or help pay the vet bill... i expect my dog to be protected against ticks and fleas for at least 12 weeks because thats what the products says and it is very expensive ... our dogs are our children and bravecto, you playing with our childrens lives!!!!