Annoyed

On Saturday 1st of May I bought MTN airtime worth. R230, made one phone call that was 1 minute long, after that my airtime disappeared, on Sunday decided to buy R10 airtime to check it out, because I tried calling MTN helpline, no answer, their Facebook page no answer, just an automated message, but the R10 airtime also disappeared, till today I have been trying to reach them but the call center is closed, I don’t know how???