Unattended queries

Please help I took a loan with Bayport and I cant afford the installment as per the contractual agreement and I spoke to them several times via phone,email and even went to their offices but they can't help me they told me that I need to write a motivational letter stating why I do I need to reduce the installment including my 3months bank statement and payslip so I need help as to is this the right procedure or not cause im facing financial difficulties. I do not want to despute the debit order as it wil affect my credit score but if there's bo assistance then im forced to do so.