How to resolve ora-06532 subscript outside of limit error?

We have Supplier portal where user can register themselves as Supplier. User has to enter few details like name , country , address, bank details and when they clicked on save it will trigger webservice and internally it will call our custom package which is having varray type input variables then we are reading the data from them and storing in our custom staging table. Whenever user enters value with & like in bank details , beneficiary name as 'Abcd&' or 'ABC &D' or 'ABC & D' . Our package is getting errored out with ora-06532: Subscript outside of limit.