It is common for kollels to make all sorts of rules and conditions to which any potential member must agree to adhere to in order to be accepted to learn there and to receive a stipend. One of the common rules nowadays is that neither he nor his family members may have a non-kosher cellphone. Having such a phone and being discovered would put the avreich at risk of losing his stipend and being asked to leave the kollel.

An avreich sent the question to Rav Yitzchak Zilbershtein, rav of Ramar Elchonon neighborhood in Bnei Braq, asking if a Rosh Kollel halachically is allowed to make the stipend he gives to the avreichim conditional on not having a non-kosher phone, and if he has one and it gets discovered if the stipend can be withheld or lessened as punishment.

Rav Zilbershtein responded that any avreich having such a device is not worthy of being called an avreich and does not qualify for the kollel stipend.

Rav Zilbershtein adds that this is also the case even if the Rosh Kollel did not make this a rule or condition of the kollel. Someone with a treif phone cannot be considered an avreich. An avreich, Rav Zilbershtein explains, is a ben torah whose entire day is focused on torah - someone with such a device does not have the ability to focus even for a moment on Torah and the beis medrash will not help him.

Further, the Rosh Kollel has the ability to ensure that the money he works hard and sweats to raise will go to the hands of talmidei chachomim and not to houses with this plague of non-kosher phones, so even if he does not use one but his wife does, the Rosh Kollel can withhold the stipend. If there is a real reason why she must have one, they can tell the Rosh Kollel and if he thinks it is justified, they will find a solution that will be acceptable to everyone involved.
source: Kikar