yes it looks a scam, as terpe has posted.
Eligibility
You must have a job offer and a Certificate of Sponsorship from an organisation that is a 4. licensed sponsor in the United Kingdom. You can only have a job offer if you will not be displacing a suitable settled worker. This means that employers cannot offer a job to a non-settled worker if it means that a suitable settled worker will be turned down for the job or made redundant.
charging you for a residency permit should be enough to warn you
