Bad product

I purchased NexGard from my local doggy parlour in December... The purpose of NexGard is to **** fleas and ticks on dogs. I made sure I gave my 4 dogs (2 pekingese and 2 labradors) the correct dose). Nowhere on the box is indicated the the tablet may have side effects and you cannot open the box until after you purchased it. On the information page inside there is just one sentence hidden amongst "warnings" that it may cause vomiting and diarrohoea in some dogs. My dogs became very ill shortly after taking the tablets. When you do research on the internet however on the website Nexguardfordogs.com - they indicate that there are much more side effects than indicate on the information page in the box - "Reported side effects include vomiting, itching, diarrhea, lethargy and lack of appetite". My two pekingese dogs had almost all the side effects - only an hour after taking the tablet, they started itching and they itched for about a week on end - terribly - I didn't know what to do. They had like a rash on their skin and still now - six weeks later - they still have dry skin and some rash despite washing in special shampoo (which was costly) and creams. They had no appetite for days, vomited and was just not themselves - was just lying around and not playing. My labradors didn't have the other side effects but had the terrible itching for days as well. I will never ever buy the product again and suggest that other people think twice before they do.