You need focus your cc spending and flying so that you have one FF account where all the miles go. Having 16 different small buckets everywhere does not help you. Even if you had the necessary miles there is no guarantee you would have been able to get the seat on the date(s) you wanted since, particularly from Europe to South Africa there is very heavy demand for these. Also, depending on what airline you eventually chose, you would have had to pay a fuel or carrier surcharge (potentially a lot of money). It might be easier to just look for cash seats in economy.