To get a glimpse into how you think on your feet while also providing top notch service, your interviewer is posing this tricky, but common, scenario to you. As you talk about maintaining your composure and talking to them in a friendly yet profession tone, make sure you talk about the need to abide by British Airways policies on price matching. As you answer, it is important that you point out to your interviewer that you would be aware of the policy if you were hired as part of their customer services team, and that you would clearly communicate that policy to the customer. If you have been in a similar type of customer service situation in the past, don't hesitate to talk about how you handled that situation, as well.