Poor service

Terrible services at Nando's Sunward Park. Went through drive ordered 4 meals, added 4 drinks (on menus showed R16 extra a drink with meals) after getting slipped showed I was charged R40 a drink. Lady said its a mistake but to late to fix it. Asked for a manager but was refused. Was then offered to credit 1 drink, not right but agreed. Then she give me R14 change and said it is all they can do.