thieveous attempt to dishonor claims

Oneplan pet insurance is terribly disappointing. oneplan has decided to reverse paid and settled claims and are now claiming that i need to pay back these funds. my pet has had treatment, i submitted the invoice and the claim was closed. again my pet had treatment, i claimed, i submitted invoice and the claim was successfully closed. this year due to a delay in treatment and invoice submission oneplan has decided to reject past claims and they expect me to pay back for those closed off claims. My pet has had treatment by a registered vetrinary doctor, invoice with details were submitted. your system should not have authorised the claim in the first place, you have authorised claims after this which indicates that all is in order. UNRELIABLE AND *****!!!