Salesforce Marketing Cloud Developer

We are looking for a developer to work on an established SalesForce set up. The database is in place and the journeys set up but there are problems with the database feeds and the journeys need amending to meet our changing needs. Journey Builder experience will be required along with SalesForce certification.
Not sure time required because I don't know how big the issue is but I estimate 2-5 days (7.5 hrs/day) initially with the possibility of ongoing ad hoc per hour support.
Independent Freelancers only please