Is a person considered disobedient to his mother if she does not return his calls, preferring his sister who speaks ill of him?

You erred by recording the call without their knowledge, as this is forbidden espionage. You have been disobedient to your mother and wronged your sister. You must repent and seek their forgiveness, while observing the rights of Islamic brotherhood and upholding kinship ties. If your sister is mistreating you and your wife, she is in error. Be patient with her and supplicate for her guidance, and seek a reconciler between you. If reconciliation is not beneficial, then shun her if you hope for benefit from the shunning.