I have Bought an Intex Aqua Mobile few months back and was using to lock with Pattern. On a fine day kids had tried to open with wrong series it failed. Once this pattern has locked after pressing more than 5 times it never unlock even though if you used the right key.
Once the Pattern Password gone the option is use third party in order to change the pattern.
Make sure Turn off your device.
Take out memory card, Sim Cards that are in the Device.
Wait for 20 Seconds.
Press and hold the volume up key button and then press the Power button it will restart for formatting.
Once the Android had restarted use the volume up/down button to select wipe data/factory reset.
Once Selected the wipe data press the power button and it asks to do again.
After pressing the power button, wait for minutes to wipe data and this depends upon the data you stored.