BAD SERVICE

I am so frustrated getting a letter of demand from MFC. Payment, as promised, was made on the 10th of January 2023 and proof of payment was sent to them. Email from MFC confirming that the proof of payment has been received. After that getting a letter that we were still in arrears and will be handed over. It is totally unacceptable and so unprofessional for a company so big. Florance is the person who received the proof of payment but did not do anything. I want an explanation why this is happening and why did I receive the letter of demand. Please start doing your work.