Q: iPhone

What bill? What are you referring to as far as billing?

The rest has to do with what exactly you are talking about.

The statement bill from your carrier? Apple has nothing to do with that. You need to discuss that with your carrier. Apple does not bill monthly.

I'm sorry, but I am not aware of any malware that could load on an iPhone and send text messages. Is this device jailbroken? The easiest thing for the carrier to do is suspend your texting, and the next thing is for your husband to restore the device to factory. Use iTunes on your Mac or PC to restore your iPhone, iPad, or iPod to factory settings - Apple Support

I cannot see how Apple has any liability in this, but maybe some others can add to this.

Diddy2015 wrote:

 

The monthly statement bill.

TThey expect us to pay.

When you receive these bills from your cellular provider, what do they claim they are for? Data usage? Phone calls? Text messages? Any other details?

The hacking of iCloud and/or iTunes accounts can be easy if one uses a simple password. Complex passwords, and now the 2-step verification and/or 2-step authentication are ways to help. Frequently asked questions about two-step verification for Apple ID - Apple Support

The only way someone could send an SMS through your account would be if you have Text Forwarding set up to their device and they were on the same WiFi network as your phone.