Ipath Diagnostics ignores my payments made

I have struggled for over a 18 months now with Ipath Diagnostics to get them to record my payments on my account. I have sent proof of payments over a dozen times. My medical insurance also paid and sent proof more than once to them. They have ignored every email Ive sent to them. They just send me statements demanding payment. Furthermore, they keep changing their bank details. Several times now the bank details are different on the new statement from previous statements. Very weird!!! I am not paying another sent to them until my account is up to date and all my previous payments show on my statement.