What are the consequences when the end consumer illegally connects appliances or increases the gas consumption?

If the supplier or the network operator finds illegal increase of the summary flow or illegal connection of appliances without its consent, which causes the exceeding of the meter measurement range or the change of the invoicing indexes in the absence of a measurement device, the supplier shall prove the end consumer that the change of the summary flow or the connection of some appliances has caused invoicing errors against the consumer, notifying him that the natural gas consumption will be recalculated taking into account the real invoicing indexes and the measurement device inaccuracy. Recalculations are made for a period no longer than one year.