HELP ! Organic Traffic Spam - Negative SEO

Hello everyone. I've been in SEO for almost 10 years now and I've never ever experience a negative seo attack like this type of organic traffic spam. The organic keywords are obviously spam they are in this form;

ozrbfysh9c9aobp1l2t_ndpus20qmqysvxwhss6o3nwdj6wjk5 oqi1spyamnpwjisszlny7imldw4udq1vgaorwrx5xczcykif4p xevpr6yc5r1dcdc9vx21nlilbxy2rlkruakmqb2tuicrk-ohtai-lajqxzl53hyg5j2n-c1j0nowkzslvniylpecyi4zy31bzdvrdr1i2kvb6tskkr3soux xtxztma9nn6s6qsqzoctwasbkvtvp9xxoik6lg_nqkwdiku0qn 7xi0tfdu_2dlevc6m-gjogij30epljyvmuzmmxf5koml0okeukskt01orfdjchk1tjbb 6vlkw


1. fbafksjfaxy9lghiwe-zsqs-fqmfkhxujgortrzl6gqch0lgctqts1w_eebqskb2u4_duxx4ln bxcqihvdsrsg0g3ob7vf9_igrtdhmrds4l3aebf-mh_jfgrzrffx1sr7szntrm34kvlx20qqz_fzqtfcqyabi5kna7 ma3lxubrcgpwtqrnqreemtpzracti_xlnop3moe7z3zuvtid1c pzj3ctyjlyu_4fqy0_kf_alail3rhvw5jgqygloydocuawdbdw usekd4uf7m05sfzaph5jf1ruvewwo1kqvivwxgohpvdlm_l6dz qp4fae-lys87blxhqndcllt7iykw

2. gi602wjqjejz46tdatkx93d9vfvrlwdrz0zrmgydjdufdwfru5 sq3daii3wsage1ic7c7-xcvp_9w5_mzdfrc72l2pj88wzwg3oegcqlg80b_ril3ge9poae u8ehebg7bb3hniawsbcecvylyrpeihpne4nwmuqqaix1atact7 od4jgepb5i8ne2gwudbijmjw7wih_ifs85mq690iqcrcsmmlrl sb0iimzpwjggh-7ra0g13uc5pasgtvpbtwvnr6xsfodzcc6bfxozzhhfstgdo4jn mggyu0ubitcktec2rhuh_cxau6vsj_lhp6saeg9j0vsbpbefv9 6s4ul3ca
3. ksdhmsc-cy4wnbhqiln2cdkt_grnz8ijukvzmn-y7u2ztktfycadfhgnbnsd_npdnqg4nsdcgnb44brln6m_yxhnh l5uxgbbx_mtzdvu0dym_xocrrcjh4iw33sx4fyzsa1owxf44bw prn2uwe3kdgleaty1q2kksg1s-sjdibhfancjs7cnubh9_-gczelvythgz8qys42mxlu6fmoartenirxoxbqmdla9myztlkn0 l6vozq_jo6oswssvecbxzw12df9ojemuvnezqkb5g7iuquptgs 5raocgodppismnbb6xphqxohoabiso2smocu1yphbvtxevnj2i pswqrg
4. emvh24ebbzsx6ghbvmkihxe1rvynupcdz1qa0txv8tvy9utvps adp742ir1k_rebylldczhxydwlcgp6xuprbziy6ks37ijavnw6 6a-b4zhzkkvg-exmrbtlxapzunqnvgutxpsgyaezjjgjxvblotslxd3kffspqic sxoekzm11bfa6vjlyb0cwtmgap64yblfppij9chfiuwlqvfgkk lb3mk-ajb0wnbfcgrp2titbdeunpk0p7majkqat9t7hs1bsgtruhi9q0 l3jo2law0a8zvbbq9czvgeerthz8bvisd4nfj7rsuijeqmfrqc fnsdbeiournmkd6f4a1fr4g

I get this type of Search Engine Terms almost everyday from my client's Pharma e-commerce site. Beginning this year 2018 we've been outranking giant pharmaceutical sites for various big medicine products and just this 2 weeks this Search Engine Terms start popping up.

Does anyone have any idea how to counter this? They do use proxies for this attack which makes it hard even for a premium wordfence to stop and block IPs.