Lancet accounts department rules depends on their mood

Lots of difficulties with the Lancet accounts department. Different employees use different rules. Approximately 10 calls per day from Lancet accounts department demanding to speak to my husband regarding an account. I told them numerous times that they calling on my number because my number was on the form with my email because I do the payments they dont want to listen and say I’m classified 3rd party! However the account they calling for is for my son that is still a minor, yet they looking to speak to my husband which becomes the third party in this instance. Two months ago there was another outstanding account and surprisingly enough after the lady called me 4 times looking for my husband she eventually sent the invoice to the email and I paid it. This time lancet is demanding money but hasn’t sent an account or invoice to neither of us.