Question
What Torah violations will occur when a person either refuses or neglects to pay aliyah donations ,membership dues and shul support pledges
Answer
A person who makes a "neder", which means that he takes an undertaking by using particular words which constitute a neder, he is obligated to fulfill his undertaking. If one does not do so, he transgress the mitzvat lo Taaseh of "Lo Yachel Devaro" he shall not break his word." (Bamidbar 30:3)
Therefore, the custom is when one makes a pledge or when the gabbai makes the Mi Sheberach after one received an Aliya, to say that "bli neder"= with no "neder" he will give such and such an amount. In this way a person will not transgress the mitzvat lo Taaseh of "Lo Yachel Devaro", since his pledge was not made as a neder.(See Sefer Hachinuch mitzvah 407)
However, even if he did not make a pledge, where the custom is that whoever receives an Aliya, a donation is made he is required to give a donation even if he did not specifically say so. (See "Sefer Hagabbai" pg. 65, by Rabbi David Spector of Bet Shemesh)
On the other hand, if there is no set minhag that everyone who gets an Aliya makes a donation and each individual does what they feel is right, even if the gabbai said in the Mi Sheberach, "Ba'vur sheyiten mattana lbet haknesset "= "so that he give a gift to the Bet Knesset", the person who received the Aliya is not obligated to give a donation. (Sefer Hagabbai" pg. 65).
Regarding dues to the Bet Knesset, a Kehilla is allowed to enforce its members to pay dues in order to buy or rent a respectable place for Tefilla. (See Shulchan Aruch Choshen Mishpat 163:a, Mishna Brura 150:b, Sefer Hagabbai pg. 83).
