Balance vanishes at Post Office account

I did an internet transfer on the 16th of February to my Post office account. Surprisingly on the 17th when i went to do the withdrawal at Thuthukani Post office in standerton, i was told only a hundred is available. Which i withdraw. I made follow ups, and do my surprise the statements says i withdraw R700 the very same day and then the R100. i never recieved the R700. the Post Office staff are very useless and not giving me any positive feedback about my money. I have been using the post office for a long time. this is the first, and very shocking. This needs an urgent response as this is my money. .....Very dissappointed customer.