old mutual refusing to revive my dependent funeral cover.

I have been with old mutual for over decade now, never had any complain until recently when i realized my son funeral cover is cancelled, i contacted my advisor who tried to revive it with no success, i sent email complaining i was told that i missed premium which i sent my bank statement to prove there was funds in my account for those months missed.

What does not make sense, the policy was on debit order and there was funds in my account, how do i miss my premium, is it my fault that someone failed to do their work?

No one is attending to my query since i sent proof to show my account always has funds.

My plea is that is fair enough old mutual refund all premium that i paid or they revive my policy.