There are a number of reasons why you may see calls with very long durations show up in your call records. When a call isn't hung up because of a bad phone set, a bad trunk card, or the caller actually didn't hang up the call, the call will usually stay off-hook until the maximum duration is reached for your phone system. At that time, the trunk will be reset and the call will be terminated.
Seeing occasional calls with very long durations is normal for some phone systems, but seeing them happen every day or week can indicate a hardware issue that you should have your phone technician take a look at.
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