From the moment since you become a user of the EuroTel GSM Global network, it is our primary duty to provide you not only a high quality service, but also a protection against the misuse of your mobile phone by an unauthorized person. That's why we offer the possibility of blocking your mobile phone in case of its loss or theft, so that it is not possible to make any calls from such a phone. The new system of mobile phone protection should stop the increase in a number of thefts, and at the same time improve the chance of finding your lost phone. EuroTel Praha is the first company to offer such service, independently of the other operators in both the Czech Republic and Slovakia, and that's why it is only within the EuroTel GSM Global network, that the blocking of lost or stolen phones is possible. To be able to request the blocking of your phone, you must know the IMEI, which is the unrepeatable identification number of your mobile phone always printed on the bottom part of the phone (below the battery), and in most cases also on the box in which your phone was packed. The IMEI is stated also on the Guarantee Certificate which you received together with your phone. As the Guarantee Certificate is an important document for you, we recommend you store it in a safe place. The IMEI is stated also on the Guarantee Certificate which you received together with your phone. As the Guarantee Certificate is an important document for you, we recommend you store it in a safe place. The way in which your phone may be blocked is, in practice, very easy. In case of loss or theft of your mobile phone, you must contact the Customer Service Department at the numbers *11 (from a mobile phone) 0800 1 80011 (from a fixed line), or 02/6701 6701, and report the event immediately. There, you give your identification data and the IMEI of your phone to the operator. The operator will then ask you to send a copy of a Guarantee Certificate by fax. The copy is used to check that the data you have given are correct. You can also ask for your phone to be blocked in any authorized shop of the EuroTel Praha company. Here also, you must provide all the necessary information including the IMEI and the Guarantee Certificate.