It is too noisy and I can’t hear the phone call through my hearing aids. 

If possible, increase the distance between you and the noise source. It is best to look for a quiet place during phone calls. This will also improve the quality for your phone partner.
Use the volume control on the mobile phone to increase the volume of the call.
If the multi-function button on your hearing aids is set to work as a volume control, press the upper button to increase the volume of the phone call and reduce the volume of the surrounding sounds.