Cashsend error 55

Can't receive cashsend anymore although I have the 10 digit number and the correct pin from the sender. Keep on getting 'Transaction not authorised 55' message. The person that are trying to do a cashsend to me have cancelled the cashsend and created a new one numberous times and I have tried different ATMs. When you contact ABSA they just say there is 'nothing wrong' or 'the person are not entering the pin correctly'. It is absolutely infuriating!