Lancet sends attorneys after a paid up account

This company seriously needs to work on their accounting and customer service. I received a message via sms last year (May 2024) after my wife had some tests done. The message gave details on the outstanding fees and how to pay. No email, no invoice, just a link to view the invoice and details on how to pay it. Paid the money, did not hear from them again. This year (March 2025), I get a call from some attorneys saying I owe Lancet money. They instruct me to contact Lancet to get a statement on the outstanding amount. I send an email to Lancet that included my ID number. I then receive a reply from them, 4 days later. The reply email says I will receive an email from them with the statement. I am still waiting for this statement. 2 weeks later, I reply to the email I received, asking again for the statement as I had not received it. 4 days later again, I receive a reply email saying there is no outstanding money on the account. Lancet, thank you for wasting my time.