Rain coming in to house through bottom of french doors!?

I would like to know what type of tradesman I would need for this job. We have a concrete platform (With steps leading down to garden) outside our back doors as house is raised about 5ft higher than the level of our garden. Due to the amount of rain we have had whoever has built the platform has not allowed for water to drain away from the house so instead it comes through the bottom seal of our french doors and wets our carpet. We are thinking of having wood flooring put down but this will not solve the problem with water drainage. We need some help but need the right tradesman for the job