Phantasmal Force spell and an opponent that disengages

As a warlock, I have a familiar 60 feet in front and the familiar is the origin of a casted spell Phantasmal Force on a target (failed save) to my front.

The opponent disengages to retreat, (assume) there is not a chance for an opportunity attack.

 The target retreats 30’, and the next turn my Phantasmal Force spell keeps up with the target.

 This continues until the target is out of range of my familiar.   (60 feet in front of me, and then 60 more feet in front of the familiar) So the target is in range for 120’ AKA 4 turns.  Assumes less then a minute.

Is this correct?

As the spell is cast from the familiar, if they move (via wings) with the target (keeping within 60’ range), can then the range now be an irrelevant variable and the spell lasts a full minute?

If I cast the spell, and stay within 60’, can I keep up with the target and then the spell lasts the full minute?

Quote from Character77006>>

As a warlock, I have a familiar 60 feet in front and the familiar is the origin of a casted spell Phantasmal Force on a target (failed save) to my front.
[...]
As the spell is cast from the familiar, if they move (via wings) with the target (keeping within 60’ range), can then the range now be an irrelevant variable and the spell lasts a full minute? [...]

 I have a question about your question :D

I'm not sure I understand correctly. Is the Familiar casting the Phantasmal Force spell? Familiars can only cast Touch spells:

Finally, when you cast a spell with a range of touch, your familiar can deliver the touch. Your familiar must be within 100 feet of you, and it must take a Reaction to deliver the touch when you cast the spell.

And well, if your question is about the Range (60 feet), that's only "how far from the spellcaster the spell’s effect can originate, and the spell’s description specifies which part of the effect is limited by the range."

I mean, if a creature moves beyond 60 feet after the spell is cast, the spell's effect (the illusion) does not end. 

EDIT: in any case, as wagnarokkr said, it's a non-movable illusion.

Quote from wagnarokkr >>

Quote from TarodNet >>

Quote from Character77006>>

As a warlock, I have a familiar 60 feet in front and the familiar is the origin of a casted spell Phantasmal Force on a target (failed save) to my front.
[...]
As the spell is cast from the familiar, if they move (via wings) with the target (keeping within 60’ range), can then the range now be an irrelevant variable and the spell lasts a full minute? [...]

 I have a question about your question :D

I'm not sure I understand correctly. Is the Familiar casting the Phantasmal Force spell? Familiars can only cast Touch spells:

Finally, when you cast a spell with a range of touch, your familiar can deliver the touch. Your familiar must be within 100 feet of you, and it must take a Reaction to deliver the touch when you cast the spell.

That's what I thought at first, but I think the idea is that they are placing the illusion on the familiar, with the (mistaken, unfortunately) idea that this will mean it moves with the familiar.

 Yeah, maybe it's that. I agree with your answer!

Gaze of 2 Minds,  allow spells to be cast through the familiar. i just assumed that would be fairly obvious when I said a warlock.

With the 60' range and it being an illusion that causes harm,  I see I mistakenly thought it moved.  Thanks for the clear up.