Western Union Money Transfers Complaint

Western Union Money transfers department,

International money transfer Other transaction issues

My employer transfered my salary through western union on - - has yet to credit my account. After many calls and lies ranging from the money was stolen by the bank and is in my account I find out that the western union in America still has not transfered the money and it with them. A second payment made a week later turned up in my account this week. Wu who denied having the payment now admit that it was their mistake. How can I make a complaint and ensure that western union are made accountable for this?