You really did not give a whole lot of information for us to help you.
Were you on any special post op diet? (Liquid/mushy/etc.)
Are you getting 40-60 grams of protein/day?
Are you drinking 50-60 oz of Water every day?
Are you restricted with sugar? (some shakes are high in sugar and can cause weight gain)
How much have you lost? (what weight did you start at?/before surgery?/since surgery?)
Did you have any other surgeries when you were banded?
How many calories/day? (you really need between 1000-1200/day in order to lose weight)
The program that I am in, we are mixed with all surgeries (band, gastric bypass, and sleeve). While it may seem, like you are not making progress, you actually might be making great progress.
Also, another way of looking at this. . . If you are like me, overweight for most of your adult life, I am usually gaining weight. If you have NOT gained weight or have lost a little ---- that is a WIN!! It takes time to about face and lose weight after being overweight. (I hope that makes sense)
What I am trying to say, is that we are not all the same. There are so many factors that affect our progress. Talk with your nutritionist, doctor, therapist and find out. Log everything that you are eating/drinking. Measure everything. Meet with your nutritionist and they will help you find the solution. You may be overlooking something quite simple, that will make the difference.
The band is not the answer. Restriction is not the answer. (It only helps with our feeling of fullness and our hunger sensation) It is a tool to get you the answer. Sorry to say, but the truth is that nutrition is really the answer.
Good luck to you.