Medical

Got a letter of demand from PRS & Associated that billed me for R660 original debt is R525.70.I spoke to Taheedah who is at accounts department at Dr T Sulaiman rooms and we agreed on paying R357 towards this amount, I made payment of R357 on the 29.02.2016 as per our agreement. All of a sudden she pushed my account to the collectors and told me that the due date was lapsed that is the reason why she did so, she was not even aware that I made payment of R357 on the 29.02.2016 until I faxed her proof hence she says their deadline was on the 24.02.2016. I was not aware until I got this letter of demand yesterday 18.04.2016, she subtract the amount paid from R525.70 - 357.00 = R168.70 that I'm owing and I'm also liable for the interest thereof and I must deal with these debt collectors. I feel this is very unfair she never explained properly and she is still doing that she doesn't even give a change for a person to speak she speaks alone hence she took that drastic stinking decision about my profile. Please advice , thanks