Unhappy customer

My wife are paying something at old mutual and I'm the one who put the money every month into this old mutual account but my problem is they keep on phoning every month they did not receive any payments but if you go to local branch for a printout the payment reflec on the system now they give her over to a lawyer and evermoth it's a different lawyer that have the case but they don't notify of any changes and it's the same lawyers account number but they keep on saying by old mutual they didn't receive any payments I don't know what to do anymore because I have all the slips of payments but if I go to the local branch they keep on saying they can't help her it's the head office that makes the chances not them