(b) No banking institution shall assert, claim or exercise any right of set off against any payments referred to in subdivision (p) of section fifty-two hundred five of the civil practice law and rules. 2. No banking institution shall assert, claim or exercise any right of set off against any other deposit account held by such banking institution unless, prior to or on the same business day of such action, notice of the set off together with the reasons for the set off are mailed to the depositor. 3. Failure to provide the notice required by this section shall not be deemed to affect the validity of the right of set off. 4. "Banking institution" as used in this section shall have the same meaning as used in section nine-f of this chapter. 5. "Depositor" as used in this section shall include shareholders in state and federal savings and loan associations and state and federal credit unions. 6. "Deposit account" as used in this section shall include shares and share accounts of state and federal savings and loan associations and state and federal credit unions. 7. If any provision of this section, or the application of such provision to any bank, trust company, national bank, savings bank, federal mutual savings bank, savings and loan association, federal savings and loan association, credit union, federal credit union or branch of a foreign banking corporation, shall be held invalid, the remainder of this section, and the application of such section to banks, trust companies, national banks, savings banks, federal mutual savings banks, savings and loan associations, federal savings and loan associations, credit unions, federal credit unions or branches of foreign banking corporations other than those to which it is held invalid, shall not be affected thereby.