Negligence of oneplan pet costing me

After a chat with a agent today regaring one of my dogs i was informed that my German Shepard is no longer on a policy. They cancelled the policy due to non payment,never ever did they informed me that they didn't receive payment! Never did they informed me the policy was cancelled. The same debit order that's been going since January now all of a sudden the account details is wrong,the same account that the debit order for my other two dogs are going off. If my dog would have been injured last week or tomorrow i would've got a huge nasty surprise at the vet, finding out for the very first time thst he has no policy! Although in april he still was on one. Now he has to be on a waiting period because of their neglect?? I am so so very dissatisfied and disappointed, repeatedly i asked them if everything is ok and up to date. All of those chats i have...never once did they let me know.