In general, yes, it sounds unusual to use 'please' and 'kindly' together. As a matter of fact, I would encourage people to avoid 'kindly' if they can. The reason for this is that 'kindly' tends to be used sarcastically and this has coloured English speakers' sense of the word. I would much prefer to read a form that said 'Please complete the form within a week' than one that said 'Kindly complete the form within a week'