Standard Bank
Interest promised on the product is not true

I have opened a Market Link account at Standard Bank on 06/06/13. The product information is as follows:
o Cash held in the account is guaranteed.
o A low minimum deposit of R5 000 is required to open an account.
o You can access your money immediately.
o Additional deposits may be made into the account at any time.
o There is no defined period of investment so funds can be invested indefinitely.
o You enjoy convenient 24-hour banking using your AutoBank card.
o You receive higher interest rates for higher balances.
o The true interest benefit is seen with investments of R20 000 and more.
o Your interest is calculated on the daily balance, and is paid into your MarketLink account monthly.
o Your MarketLink account can be linked to your existing AutoBank card, his allowing you to manage your MarketLink account using our self-service channels.
o Fees are applicable when transacting on the account

On the first July 2013, i had only received R35 interest on this account. i have R20000 invested on this account. This is the second time i have invested this much money. i also invested in April and received not a single cent. How can this be?