There are 3 possibilities
a) Digitizer went bad. -- you would replace the digitizer to fix this. Follow the iFixit tear down guide to replace the digitizer. Normally its easier to replace the LCD + Digitizer at the same time.
b) Digitizer cable is loose. -- Follow the iFixit tear down guide to open up the phone and check the cable.
c) Logic board is bad. -- Follow the iFixit tear down guide to open the phone up to change the logic board. However, if it comes down to this, you should look to get a new phone.
Alcatel One Touch Fierce Teardown
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It sounds like the digitizer might be bad. From the teardown guide on the device page I suspect the digitizer may be in the LCD display. There is no guide for it as yet but the teardown might help.
Alcatel One Touch Fierce Teardown
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