BAD SERVICE, ACTUALLY NO SERVICE AT ALL

I had an amount owing to Bonitas, after receiving a letter making me aware of this I phoned to make an arrangement and was told to send an email as arrangements are only recorded if sent by email. I sent the email early February but there was never a response, after numerous emails they finally responded on the 16th of February acknowledging my email and confirmed that the payment arrangement is noted. End of February I made my first payment, to my surprise they handed over my account to debt collectors to harass me as if I don't have an arrangement in place. Why did they confirm the payment arrangement if they would later hand over my account. Why did they even hand over the account. I phoned they customer care and the lady I spoke to says she can't help me as this is a credit control issue, I ask to speak to them for clarity and she says they don't take calls. How will I get answers to this. This is pathetic and sickening, bad service at it's worst. Membership number : ********** 4625