After the IOS 15.7.8 update on my iPhone 7s I cannot answer calls using speaker/microphone. The microphone works for voice memo, and I can answer calls using airpods and Bluetooth.

If you have a hearing or sound issue on your device then please try some of these processes to set it right

1. If you have a distorted sound issue on your iPhone --> If you hear no sound or distorted sound from your iPhone, iPad
2. If you are not able to hear the other person, click this...>If you can't hear a person on a call or voicemail or if the sound isn't ...
3. If you only hear through speakerphone mode --> If your iPhone is stuck in headphone mode - Apple Support
4. If the other person is not able to listen to you then please click this to identify the issue --> If the microphones on your iPhone, iPad, and iPod touch aren't ...

If the above options do not mitigate the issues then Contact your carrier and then Contact Apple Support

There are several potential reasons for distorted voice calls on an iPhone. Here are some common factors that can contribute to this issue:

1. A weak or unstable cellular network signal can result in voice call distortion. If the signal strength is low, the audio quality may suffer, leading to distortion, dropouts, or static during calls.
2. High network traffic or congestion can affect voice call quality. When there are too many users trying to access the network simultaneously, it can result in degraded call quality or distortion.
3. It's recommended to keep your iPhone's software up to date and regularly check for app updates.
4. If you are using a Bluetooth headset or speakerphone during calls, interference or compatibility issues can lead to distorted audio. Try disconnecting any connected Bluetooth devices and check if the voice quality improves.
5. Voice call distortion can also be attributed to problems on the network provider's end. Temporary network outages, infrastructure issues, or maintenance work can affect call quality in specific areas or during certain times.

If you're experiencing persistent voice call distortion on your iPhone, it's recommended to troubleshoot the problem by following these steps:

1. Check your network signal strength and switch to a different location if possible to see if the issue persists.
2. Restart your iPhone to refresh the software and temporary settings.
3. Disable any Bluetooth devices connected to your iPhone during calls and check if the distortion improves.
4. Verify that your iPhone's software is up to date and install any available updates.
5. Contact your network provider to inquire about any known issues in your area.
6. If the problem persists, consider contacting or visiting an Apple authorized service center to diagnose and address any hardware-related problems.

Get a Genius Bar Reservation and Apple Support Options - Apple

When you encounter issues with your Apple devices, the Genius Bar at Apple Retail Stores is the go-to place for expert assistance. The Genius Bar is staffed by knowledgeable Apple employees, often referred to as "Geniuses," who can diagnose and resolve a wide range of hardware and software-related problems. To ensure personalized attention and a convenient visit, Apple provides the option to schedule a Genius Bar Reservation.

Contact Genius Bar.

Manage Reservations - My Reservations - Apple

Take your device to an Apple Retail Store or Apple Authorized Service Provider, or contact Apple Support:

1. If you prefer face-to-face assistance, you can visit an Apple Retail Store. Apple Retail Stores are designed to provide a hands-on experience with Apple products and offer support services. You can speak with Apple specialists, known as "Creative Pros" in some locations, who can assist you with product-related inquiries or minor troubleshooting.
2. In addition to Apple Retail Stores, there are Apple Authorized Service Providers (AASPs) that are authorized to perform repairs on Apple products. AASPs are independent businesses certified by Apple to offer service and repairs for various Apple devices.
3. If visiting a physical location is not possible or convenient, you can seek support by contacting Apple Support. Apple offers various channels for support, including phone support, live chat, and email. The official Apple Support website provides information on how to reach out to Apple for assistance.

Finally, you can also start a repair log or track the status of existing repair --> Apple Repair and Repair Status Check - Official Apple Support

In summary, Apple provides customers with a range of support options, including the Genius Bar Reservation system, visits to Apple Retail Stores or Authorized Service Providers, and various channels to contact Apple Support for assistance with their products. These services aim to ensure that Apple users receive the necessary help and support whenever they encounter issues with their devices.