I may be wrong but I think these could be mortgage participation bonds and as you state your funds are locked in for 5 years.
I don't think there is anything wrong with this investment class but you really need to sit down and look at your whole investment horizon and decide how much you want to invest in different classes of investments. Also there is no way that you can exit these instruments ahead of time unless you can prove "necessitous circumstances" which could be medical or death, but there will be penalties raised for early release
I would suggest that you look at structuring an investment portfolio, consider what you may need in each class of investment and if a component is investing in the stock exchange then read up and attend seminars on how to invest - banks at one stage used to run such courses as did the JSE from time to time
Finally ask question of this forums community - never be afraid to ask question even those that may seem silly to you - nothing worse than getting your fingers burnt because you failed to ask a question
Good luck
