Went 15/04/2022 for my nephews birthday. Told 1 hour wait as busy … fair enough it was Easter Friday. Ordered 3 starters arrived no side plates so nowhere to put eaten wings. Went to bar to ask for side plates (5mim wait). This is where things really went down hill. Mains arrived and I’d ordered double chilli burger. Burger arrived with no chips so I found the waiter and told him this and he told me there were none as it was a vegan burger. Told him I didn’t order vegan burger. He went to kitchen and came back few minutes later with a dish of chips and assured me apart from the chips my meal was correct and real beef burger and left . Bit into burger and I’m made aware it was not real beef and was vegan beef( also no onion rings or cheese sauce) so either the waiter or chef was lying. This was very dangerous as I’d advised staff on arrival that I was allergic to some seeds and grains (which are found in veg burgers)Back to bar where I waited 5 min for young girl to serve me and explained this. She advised me to wait a min while she checked my order on till as she is doing 100 things at once. She confirmed I’d order chill burger but kitchen closing down (at 730pm)and I can have refund for my main if I wanted(which I advised didn’t want refund). Another lady who seemed more senior came over and I explained situation and she came to my table and confirmed my burger was vegan and order wrong . Advised me she would get kitchen to get my correct order but might take 10 min or so . Nephew finished his meal before my meal arrived and was pestering me for dessert so I went and ordered . Senior lady advised me his desert was on house which I appreciated . My meal arrived as nephew finishing desert and this time no cheese sauce or onion rings or knife and folk . Back to bar for 5 min wait to tell same young lady this . Advised kitchen were opening a bag to make onion rings then walked off no apology . 15 min later still no onion rings so left half my meal and left . Very unhappy after spending over 40 pounds. I used to work in the industry and understand mistakes can be made but to get the second order with missing items is a joke. I was calm and polite but intentionally or not I was made to feel like an awkward customer which I’m not . Also can’t of been closing as before I left I saw people ordering food well after my order so somebody lying again . When I got home Made a complaint on sizzler web complaints and few weeks no reply made an over complaint 3 weeks ago still no reply . So they are obviously not bothered . I’m not after a free meal as you couldn’t pay me to eat there again I was just hoping they would train there staff in the dangers of food allergies and customer service.