If your insurance policy is about to lapse, the insurance company will usually send you a notification of intent to cancel. When you receive the notification, you will have a few days to get the situation corrected, such as paying a late premium, after which time the policy will lapse and your coverage will be gone. If your insurance lapses before you get the situation corrected, you will have to seek coverage through another policy.
Once an insurance policy has lapsed, you may or may not be able to get it reinstated. Some types of insurance, such as life insurance, can be reinstated by bringing the policy up to current. Other types, such as home or car insurance, cannot be reinstated and you will have to purchase a replacement policy. If you have a mortgage or a car loan, allowing your insurance to lapse could result in the loan being terminated.
Contact your insurance company as soon as you find out the policy has lapsed. Explain your side of the situation and ask the customer service agent how the situation can be corrected. If it is a matter of bringing the policy up to date, the representative will inform you of the amount owed and a date the payment must be received by. Failure to get the policy back in force within the specified time will result in the policy being permanently canceled.
If the policy cannot be brought back to current, you will have to find another insurer as soon as possible. To do that, you may want to try getting a free online insurance quote from a brokerage such as this website. Because a brokerage represents multiple insurance companies, they can usually provide you with more options and lower premiums than you can expect when buying from a single, dedicated agent or company.