Poor Service

I requested a arrangement letter for my account on the 23 January 2015,I was told my the consultant that I will receive the letter on Monday the 26 January 2015.On Thursday the 29 January 2015 I still did not receive it,I phoned in the morning and spoke to a lady named Bianca she told me I would receive the letter the same afternoon but till now I still did not receive it.I again phoned in Friday morning the 30 January 2015,I was transferred from one person to the next but still no assistance,I was told someone will call me back I'm still waiting and I need the letter urgently.Why must I wait a whole week for a letter.