MBD is refusing me an arrangement letter

I was unemployed for over 6months as a result I couldn’t pay my debts now i got a new job and before i sign an offer letter they need me to provide an arrangement letter. MBD is requiring me to pay 3 months in advance before they could provide me with the letter...my question is how will i pay when im unemployed? Im trying to fix my things here and you guys are not giving me a chance yet you harrass me everyday with your phone cally