Explanation letter to a panger complaint...pls help me to write as this is d 1st time n im cluless?

he was complain abt crew on d flt not answering d cal bel for 45 min.....not getting a gl of water n not providing a extra pillow to his pragnat wife(flight was ful n we didnt hv any extras)entertainment system not working,crew sleeping when he came to d galley(only 1crew member was seated at that time cos of a headache)as d other crew memebers were too busy attending to al d individual requirments