Negligence of handling policy(investment)

I switched my banking details and as a responsible long term holder of a greenlight(old mutual) policy i logged onto my old mutual profile and updated my bank details successfully or atleast I thought. I recieved confirmation that my update was successful. I then phoned old mutual the following month when I realized that they didn't deduct to find out why was this the case. The service agent confirmed my new details but was unable to explain the non payment. She said she would resubmit the debit order. Month later I realized that nothing went off and I phoned again. The service agent said that my policy had lapsed and acknowledged that it was an error on their side and offered to revive my cover. I was sent revival forms which I completed and sent back but I was asked to resend which I did a couple of times until another service agent confirmed receipt. Thereafter I never heard from old mutual. I kept calling and sending emails but there was no direction when I called and no response to my emails. Today someone called me to offer me a new policy which I rejected and advised that I need the existing complaint resolved. This policy is +-10 years old and would not make sense for me to let it lapse when I have the means to pay my premiums. It would only makes sense to old mutual to let it lapse because there is only one clear beneficiary in this situation..