An agent offered me a free sim card not porting

An agent or sales,rep came to,my house and offered me a free Cell C sim card. She asked for my current number which is not Cell C, my date of birth and name. An sms was then sent at 16:20 and she,wrote the number which I later saw it was an authorization number 8482 to port from ***. I only realised after they left that they were porting my mtn number *** to Cell C. I then called the call centre on *** at 16:26 an spoke to Yolanda and,she said there was no porting request on the system I must call after 15minutes. I did until 16:44when Lerato said I must call them the next day. I told her I,already got two sms,s about porting with ference ***CELLC***. She said there was nothing on their system. At 19:41 I got an sms saying my porting request was successful,and will finalise at 23:59. I call them again spoke to Pearl who told me potting department only operates between 8am-5pm and she kept me on hold until my airtime ran out. Today at midnight I will loose my airtime and data bundles. Pls help.