Asked for no Garnish

I've been a customer for a long time now and this has to be the worst service i have ever received. I ordered a share box at the drivethru with extra chips. I asked very nicely that i do not want garnish as i am allergic to onions and gherkins. When i got home the burgers had onions on and there weren't any extra chips. Unfortunately i couldn't go back as i didn't have transport. Ive always loved McDonald's but this really was disappointing.