What you say is what you shall reap
The mistakes that brands and agencies make on social media have been talked about a lot. The problem here is not that agencies or brands lack something like a structure to deal with such mistakes; it is more to do with knowing what needs to be done in some unforeseen and undesired situations.
Social media is a place where the brands and services are most exposed to both appreciation and flak alike. The last thing one can do on social media is to remove negative comments on their pages and especially if you are a brand like Starbucks and have disgruntled customers talking about you. If there was a faulty service or a product, the best thing is to accept and promise to resolve. The agency executive or the social media manager may not know the exact reply but is there any person on the client side who may know it? It could be someone from the customer care team or the legal team or any other team who may be equipped to resolve the query in the most appropriate manner. We at our agency have created a simple process to seek the answers from the right people before going out there and replying! The key to resolving such issues is patience and the right intent.