Found a piece of glass in my drink at Whitefield’s brewery

I had gone out for dinner at a leading brewery in Whitefield. I was slowly having my drink and then in one sip I realised some kind of granular thing on my tongue which pricked it. I was appalled to see it was a fine piece of glass! I immediately called the waiter to which his response was a simple sorry and an offer to replace my drink with a new one. I asked him to call the manager and after waiting for 15 minutes some lady manager showed up who simply just apologised and asked me what she could do for me. I told her to take the matter seriously and understand the severity of the situation and that I was scared I might have swallowed another fine particles of glass. She kept saying sorry and agreed to waive of the drink charges as I thought waving off FOOD + DRINKS amount won’t be fair (Ideally they should have done this). I asked for an official apology in my email however I have not heard anything from then despite followups. I had also told her that I shouldn’t have to come again for this issue to their place but in vain. Be careful fellas! Eat and drink slowly and mindfully. This issue would have been seriously impacted my internals. Will appreciate your views.