I have had this problem a few times and the process to have it resolved is rather straight forward.
Contact CGC, explain the issue, CGC will, perhaps, ask for a photograph of the damage, CGC will authorize a return for a ReHolder, and, in a email, explain the necessary steps to have your comic book ReHoldered for free and be reimbursed for the cost of shipping the comic book to CGC. CGC will ship it back to you at its cost.
The last time I had to return a comic book whose slab was damaged during shipment to me from CGC was in 2000, if I correctly recall, and the CGC customer service representative, as always, was extremely helpful in resolving the issue.
Edit: I failed to note that none of the comic books I received whose holders were damaged during shipment were themselves (correction) undamaged damaged and, thus, retained their grades. Based on the photograph you provided, the comic book does not appear to be damaged as the sleeve likely protected it as the slab is not, relatively, badly damaged (almost the entire bottom broke off from one of the damaged slabs I received).