Is this mental abuse???

I work for a home care agency, and had to call off due to sickness. Another nurse came to sub for me. All we are contracted to so is a complete physical assessment and whatever is in the care plan. This particular patient has a mental illness and she needed her medications passed to her. However, the sub has told her that she can be her nurse instead of me and she will help her take care of her and her kids. She doesn't even have legal custody of her kids, but they spend the night sometimes. She has also given the client her personal phone number, which we are not allowed to do. The sub told her that she can call her anytime. In my client's mind, since the nurse lives closer to her than I do, that she can call her for emergencies and she will come. Well, that's not in our job descriptions, and the county doesn't allow us to do that. This is not even her client! According to our policies,we can not give out our phone numbers out or do anything outside of the care plan. Well, the client also has an independent provider that helps her with errands and other social needs. The independent provider was PISSED that someone came in to promise her things that we as nurses are not allowed to do. She said that if our agency doesn't fix it, she's reporting the sub nurse for mental abuse because it has caused her "anxiety." The client herself told her that she loved me and did nothing wrong. I explained to the provider that the client is not to have our phone numbers or call us for "emergencies," or respond. I guess my question is, could someone making false promises considered mental abuse to a mentally ill patient? What can I do?