Sending a debt collection agent to phone me after Bayport has debited me

I have had an account with which has been in arreas for a long time due to financial struggles and employment.

I recieved a call in July and made arrangement for August debit order which went off on the 25th of August, 3 days after I phoned in at Bayport to enquire about an sms I had recieved previously of a settlement discount if it is available so that I can pay and close the account in September, The consultant told me it was no longer available, however a month ago I had been told by another consultant that i needed to make payment then I can call in for a settlement discount(clearly I was mislead).

Today I recieve a call from a collections agent saying my account has been handed over, after the debit order had already gone off with Bayport, the collections agent says I should make another arrangement with them for payment.

I phoned bayport to get clarity, the consultant says the account has been handed over since March (I did not recieve a call from the collections agent in that period of time), I have to make a new arrangement with the debt collectors after honoring my payment arrangement on the 25th of August and calling in at Bayport and being told the account was active with them.

After speaking to the Bayport consultant I recieved a text message notifying of a Sept debit order with a different reference. How legal is this? Could she sent my bank in details to the collections agancy without my approval?

Bayport how legal is this? You debited me, I was told the account is active, after paying now my account is handed over????????

All I want is a settlement discount so that I can settle this debt in September. CLARITY PLEASE ON YOUR PROCEDURES