Broken sewing machine

My mother bought a sewing machine in February this year from a Best home & electric store in Mankweng (turfloop). Sometime last month the machine started giving her hassles and she returned it to the store. After being promised several times by the staff at the store that her matter is receiving priority, she is still sitting without her sewing machine to this day. The machine is still covered by gurantee/warantee but the store is playing hide and seek with her. She is expected to continue paying her monthly installments even when her dressmaking business has come to complete halt because of the delays in replacing/repairing her sewing machine. This is uncalled for. Please attend to this matter ASAP because if she had missed a month's installment, you would be sitting on her neck like an abatross.