Payment not received, poor service, incorrect company details

I took a loan out in March 2019, due to been in hospital I settled the account in two payments. I even emailed proof of payment to ***. It's been a year, I received an email from debt collection attorney requesting that I settle the account, which has been in arrears. Shapiro Shaik Defries and Associate. What must I do pay double, I am so confused. Can anybody help or advise me?