What kind of offences and where have you got the information from that they haven't been recorded?
If it's a site like the crime statistics map, do the crimes you are reporting qualify as to what is reported? Could it be they have been recorded but not reported?
Alternatively have you contacted them to find they have no records of things you have previously reported?
Who have you dealt with about the crimes - do you report say via 999 or local police station or a local community support officer?