Verbal Abuse

Hello. I am a Music Composer. I have composed a song for a client who is a NRI working in Germany now. The work has come to a halt and he paid me for the work done and I need to deliver the finished song. It's a 1 day work to finish the patchwork and deliver him. But I am under some medical treatment due to health issues with my head from more than 1 month now. So I couldn't work and I didn't work for any project in this time. But I didn't mention this to him because I feel stress in communicating with him and also I lost some respect on him due to his way of handling things in this project before. So I just blocked him on WhatsApp temporarily. But I am available through direct calls. Once I am little fine I wanted to finish that little work and deliver him. After 1 month he texted me on Google Pay speaking very abusively indirectly abusing my mother or father too. I am shocked of his response. Because he is educated and a working professional that too a NRI. I am available through calls directly but he didn't call me even once after that or he have another choice of corresponding through the lyricist for this project. I texted him on Instagram and called him so many times after that immediately. But he blocked me on Instagram, Google Pay and not lifting my calls. I felt so hurt because of his abusive text message. It hurt my self respect. I want to complain about him regarding online verbal abuse. Please guide me on this. Thank you.