Very bad customer service

My Mother Audrey age 68years bought a double bed from Lewis on the 13/06/2014 second last week in October 2014 the bed's base broke. I contacted the branch because the bed is still under warranty. Since then nobody came back to fix or replace the base of the bed. I spoke to Romeo the branch manager over the phone and went to the branch but still nothing was done.the stock controller Nomsa made promises but never came back to me. I called several times and every time they have a story. Two weeks ago i phoned the head office spoke to lady called Naledi and was promised that someone will contact me me but still nothing. Yesterday 10th of February 2015 i went to the branch again and was promised by the manager Romeo that i will get the new base before the end of the working day. Today 11th of February 2015 and still sitting with a broken bed that is costing us a fortune. The prive they charge my mother that is a pensioner is three tes more then what they pay for at Restonic beds. Please help us get a new bed.