Unpaid pension fund

The past 3months my grandfather hasn't received his pension fund. I've tried to email them in February and they requested a letter of existence and they even rep**** that they got it. In March still no payment has been made when I try again to email them they told me that the letter of existence certificate that wev sent the figure print was not clear enough, I tried to do another letter of existence and sent it to them still I got a confirmation email and stop no payment when I try to call them they hang up their phone or they don't pick it up at all. PLEASE HELP MY GRANDFATHER'S INSURANCES HAS LAPSE AND HE IS 92 YEARS OLD imagine if anything can happen what will happen to the old man.