When you purchase a new phone online or from your local retailer, you often pay very little or nothing for it up front. In return, you agree to stay with your network carrier for specified amount of time and pay monthly charges based on the agreement. This specified time is called "in contract" period. This contract period is usually 1 to 3 years and depends on how much money you put down and what type of plan you subscribe to.
During the "in contract" period, your network carrier will not allow you to unlock your phone. This is the time period in which they claim to recover the investment that they have made in subsidizing your phone. However, if you use a 3rd party phone unlocking service, you can unlock most "in contract" phone quickly and for a good price.
There are examples where "in contract" phones may have a lower percentage of unlock success. Eg: until recently, Nokia Lumia models could only be unlocked with about 70% success rate if the phone is "in contract". If phone is out of contract, then success rate is 100%. We have found an unlock solution recently which increases the unlock changes even for "in contract" phones. Another example is to unlock finland iPhone Sonera. This iPhone can only be unlocked if the phone is out of contract. T-Mobile network also enforces this rule very stringently. Of course this is true as of this writing. As new unlock methods become available, the success rate and cost of unlocking these devices also changes.
Most phones however, can be unlocked while they are still "in contract". But before a phone can be unlocked, you must have it activated with the network that you bought it with. For example: you buy an iPhone locked with AT&T and the retailer will give you that phone with instructions on how to activate the phone with AT&T network. When you bring home that phone and purchase an iPhone unlocking service without activating it, the unlocking service will NOT be able to unlock that phone for you. You must activate that phone with AT&T by following the activation instructions provided by the retailer/manufacturer. Once phone has been activated, you can purchase the unlock service after which it can be unlocked.
If during the contract term, you report your phone as stolen if you are late in paying your bills, your phone may be listed as blocked or blacklisted by your network carrier. Simply what the means is that you cannot use your phone with your network or any other network. Blocked or Blacklisted phones are a little more tricky to unlock and also may take a little longer. This is most apparent if you have an iPhone. Unlocking a blocked or blacklisted phone success depends on the network that has placed that block. AT&T phones with this status are easier to unlock than Verizon phones for example. Due to the time duration that it takes to unlock Verizon phone with this status, most suppliers do not offer this service. Also the process much more costly and success rates are low. For Verizon blocked phones, you will see that this service is not listed on many sites.
Most phones however, can be unlocked while they are still "in contract". But before a phone can be unlocked, you must have it activated with the network that you bought it with. For example: you buy an iPhone locked with AT&T and the retailer will give you that phone with instructions on how to activate the phone with AT&T network. When you bring home that phone and purchase an iPhone unlocking service without activating it, the unlocking service will NOT be able to unlock that phone for you. You must activate that phone with AT&T by following the activation instructions provided by the retailer/manufacturer. Once phone has been activated, you can purchase the unlock service after which it can be unlocked.
If during the contract term, you report your phone as stolen if you are late in paying your bills, your phone may be listed as blocked or blacklisted by your network carrier. Simply what the means is that you cannot use your phone with your network or any other network. Blocked or Blacklisted phones are a little more tricky to unlock and also may take a little longer. This is most apparent if you have an iPhone. Unlocking a blocked or blacklisted phone success depends on the network that has placed that block. AT&T phones with this status are easier to unlock than Verizon phones for example. Due to the time duration that it takes to unlock Verizon phone with this status, most suppliers do not offer this service. Also the process much more costly and success rates are low. For Verizon blocked phones, you will see that this service is not listed on many sites.