Bad service and no feedback

Bad service received from Mercedes. I app**** for contracts to be changed in February. They said I must send statements, proof of insurance and the letter. I did that after being sent from pillar to post. They sent email to say it will take 3 -5working Days. I didn’t get any response. I kept on sending emails for follow up. The last straw was calling them again last week to ask to speak to their manager. They promised the manager will call, upbuntil this day I’m still waiting. After my call to request a manager. I emmediately received an email to say my application was declined. Declined with no reasons stated. I call again they promised someone will get back to me. I’m still waiting. I received another email that says now they need payslip. After I told them numerous times before that I’m not employed.