Not saying you shouldn't complain, but you do need to understand the licence claims that Frontline has before complaining. Firstly it does not prevent ticks from attaching. It does claim to kill them between 24 and 48 hours after attachment. Secondly the kill time for fleas is also 24 and 48 hours. If you have just been using regular frontline have you been using environmental control in the house? If you haven't they will question whether this is actually the problem. The kill time with the new products such as Advocate, Advantix and Stronghold is between 20mins and 2hours.
April my dog had a tick removed at vet, last month the cat had a tick, now dog had fleas! I religiously do all 3 animals every 4 weeks With frontline.... Just written to them informing them my vet has stated they have seen a resistance to Frontline, I've used this 15 years Double doses them last week and with 6 months left I have written asking for a refund and if I don't get satisfaction I'll go to watchdog! This is a disgrace people don't want fleas in their home and it's an expensive product, I'm very fed up and see there's a massive problem on here