What is the rule in a medical insurance company sending you notice that dependent covered back January but were never notified until end of September?

The rules regarding the notification of changes in dependent coverage vary from country to country and depend on the specific laws and regulations in each jurisdiction. In some cases, there may be specific timeframes within which insurance companies are required to notify policyholders of changes in coverage. If you have concerns about your insurance coverage, it's important to contact your insurance provider directly to inquire about the specific rules and procedures that apply to your situation. They can provide you with accurate and up-to-date information regarding the timing of notifications and any other relevant details. Additionally, you may want to review your insurance policy documents to see if there is any information about notification procedures included in the terms and conditions.