Airtime Not Going Through

I Bought Airtime From A Vodacom Vendor. When I Tried Redeeming It, It Kept On Saying That “Voucher Invalid”. The Vendor Didn’t Take It As He Said There Is No Refund On Airtime, When I Called The Vodacom They Said The Voucher Hasn’t Been Used But I Can’t Redeem As It’s Invalid. I Don’t Know What To Do With The Airtime Vouchers And My Money Lost…