The only way that example could be correct would be if it were read like this:
We are waiting to help you while you are building your strong future.
If that is not the intended meaning, then the example should correctly read:
We are waiting to help you build your strong future.
As ‘strong’ also seems a strange word to use there, I suspect the example is wrong and was likely to have been written by someone who does not speak English as their first language.
‘Secure’ would be a far better word.