Poor service and communication problems between credit company and their clients ????????????

I’m totally fed up with this company! Constant harassing of telephone calls for an Woolworths account already paid up! I have all bank statements to prove that my debit order ran and acc was paid in full beginning of January 2018! The Woolworths acc was settled with MBDCS and when I finally got a response from them to get a copy of paid up letter which they promised they would send in 2018 they told me the account was no longer with them I must contact Woolworths! Now my mom being harassed daily with phone calls from Daly Corp who also does not respond to emails sent to them! All I got was the amounts was paid to MBDCS and not them and they can’t help me I must contact MBDCS! So it’s a like a tennis match trying to sort this out! And no one can explain where the amount they requesting is coming from! Somewhere along the line there communication problems! It’s so frustrating they quick to harass you but no one can explain anything to you! I have sent them several emails with proof of payments to which I don’t get response to! I’m currently out of the country therefore I communicate via email! I also receive emails from them requesting payment and say if amount paid to ignore the email but the constantly harass! This account is paid up in full and the amount they requesting is way above what my credit limit was!