Got a co-op but CPT authorization is delayed

So I got an offer after months of grinding and the start date is 10th June, went to ogs to ask for getting my cpt approved early before the joining date but they were adamant that it will take 15 business days and I can expect the CPT to be approved by 21st June at the earliest. My offer letter mentions 10th June as the joining date, any ideas on what I can do next?