Hey we have all been there! i feel your desperation, but resist if you can.
it will not be good for you in the long run!
If you do it for 2 weeks or less i guess it wouldn't harm you because most fad/crazy/unrealistic diets (that are not necessarily nutritionally complete) are only ever recommended for 2 weeks...so i guess you could use this as a comparison.
The shakes are 250 calories, and you can actually eat a decent amount for that, why not have a 250 cal meal instead, if you are set on doing this?