Outsurance no claim bonus not paid

I am struggling to get my no claim bonus from outsurance. They sent me an email and sms saying it would be paid on a specific date, but no monies have arrived in my bank account. My emails go unanswered, and the call centre agents are very pleasant but they cannot provide me with an actual proof of payment from the bank and they cannot put me through to their payments department or a manager so we can get this resolved. I've phoned 3 times. I've sent a message on FB Messenger. No reply. Has anyone else had this problem?