Bad service

Hi I ordered a milkshake on the 4th of November 2019 the milkshake was off but I did bring it to the managers attention which he said he would get back to me and he didn't. Sent an email to head office of steers and still no response. The staff member did taste the ice cream and she acknowledged its off. But it's not the first time this has happened at steers. The lack of customers service is very bad. Even the manager and head office isn't bothered