Traded in an S21 for a S23 ultra in March 2023 based on a promotional deal Verizon offered via email. Contacted Verizon and received a mailing label to return the S21 and did so. After 3 months no credit was applied. Two succeeding chat sessions, one in May and one in Sept both assured me that the credit would be applied within 1 or 2 billing cycles. This has failed. Phone contact with customer support 11/20/2023 (Tony), indicated that the credit would be applied in 7 business days and to check back if not. Naturally no credit was applied. Second phone contact with customer service on 12/12/23 (Patrick), indicated that the issue was resolved and that it would be applied the next billing cycle. Still no joy. This is a recurring issue with Verizon and there is no indication that anything is being done to rectify this issue.