Samsung monte is in "No

Don't worry about it. it is very simple to Unlock your Samsung S5620 by entering Imei Unlock Code . you can get your Mep Unlock Code for Samsung by third party or your network provider.
third party give your Imei Unlock Code within hour. but your network provider take time to give you Imei Unlock Code. and charge huge amount. you can buy Samsung Imei Unlock Code from third party. they will charge little amount.
i hope this will help you.

Hi,
If you are trying to use a SIM card in your phone and getting a message like "Enter Subsidy Code", "Incorrect SIM Card", "SIM not provisioned" or similar messages, then you need an unlock code for your mobile phone. You can get Samsung S5620 Unlock Code from the network provider, they will verify the account holder information. They can open up all networks for you where you want to use your phone. Once your phone is unlock, it will work with any network worldwide without sticking to one network. You can check Samsung Unlock Code site, they will provide you an accurate code fast with easy to follow instructions on how to unlock your phone, for the lowest price.

Hope it helps.

Thanks.