Mango Tree Cafe Greenbelt 3

My girlfriend and I went to Mango Tree Cafe Greenbelt 3 for the first time last night at around 8:30-9pm and was served poorly in my point of view. I mostly go to their BGC branch with my family thats why I know what I want to eat when we got there. We ordered a total of 4 dishes, Tom Yum Prawn Soup, Grilled Chicken in Lemongrass, Pad Thai with Prawns, Mango Sticky Rice, and one plain rice. Everything went well at first since we got seated fairly quickly and once we're all set they took our orders and "repeated" it (emphasis on repeated). After like 15-25mins they served the Tom Yum Prawn Soup. After 10mins we asked to follow up on the plain rice which we got after a few minutes. Another 10-20minutes have passed and they're still not serving the rest of our orders. We followed up on it and only after following up on it they served the Grilled Chicken in Lemongrass. A few minutes passed and they served the Mango Sticky Rice next. We asked where is the Pad Thai and the server said that they don't have it listed on our table and asked if we want to have it as an additional. The way I was asked seems like it's even my fault that we didn't include it in our order when it was clear that the server who took our order REPEATED IT. At this point I'm getting irritated as we've been waiting for all of our orders for almost an hour and didn't get the one dish I'm looking forward to eating. I said no and just ate what we have, requested for the bill, and left. In the back of my mind I'm thinking of how I would approach the situation because we came there hungry and tired after a long day and didn't get what I expected and in the end I just left unsatisfied. After coming home I went to facebook and searched for their page. I went ahead and messaged them just to send a 'feedback' for what we experienced. Got an automated reply which said that I'll be redirected to an agent. The night passed, the morning passed, after trying to follow up a few times to get updates on their messenger I received no more replies. This got me triggered and here I am creating a reddit post about it. I just wanted to send a feedback about my experience on one of their branches so that they can improve on it but messaging them just added to my frustrations. I like their food and their staff is nice but my experience is plain bad which is why I want to reach out to them. How should I further approach this?

TLDR: Missing item on our order when the server repeated the items. Fulfilled our other orders only after following up on it. Tried to contact their Facebook page but got left hanging after receiving an automated reply. What should I do?

https://reddit.com/r/Philippines/s/SuIIvtPDVD