Poor service

Vodacom is billing me twice, I do not receive invoices I*** & I*** My mom had passed away, dad went to vodacom as mom' contract upgraded and then they told him they can transfer it into his name, which they did!. Now they handed him over for moms' old number *** and still billing his bank acc ? I have called Vodacom the whole morning, spoke to 5 different people, of which the one Vino send me invoices but with a wrong surname, I have to keep calling back and no one can properly help me as I do not have the cell no that this invoices pertains to!!!!