We take it as our duty to make sure our clients are made aware and educated of important information and risk associated with incorrect or invalid steps when dealing with malware cases as we have years of experience to handle malware issues on websites but our clients may or may not be having the expertise to handle such cases. So when asking for old data backups kindly be informed of the same as follows:
1. Never reuse any infected data if you do the infection may repeat again more often.
2. If you think that you will antivirus scan and reupload the website codes the same will not fix the issue and such issue may repeat again as any PHP encrypted malware codes in any file may be skipped and not picked by generally file antivirus which we use on our desktop software as the way website malware works are way different than desktop computer virus infection cases.
3. If you are not having expertise in handling such cases for your help we have Kb articles mentioned at
https://billing.webji.in/knowledgebase/4887/Why-malware-website-are-not-allowed-to-host-and-what-it-may-cause.html
https://billing.webji.in/knowledgebase/4884/How-to-secure-my-website-What-basic-steps-to-follow-for-it.html
So after reading this all information and making yourself aware of what to do and what not to do. Onetime backup can be provided which you can download however reuse of any such infected data if recreate the issue may result in an abuse fee if the issue repeats again in 90 days time frame.
As a service provider, our goal with this article is to make you aware of the same. Rest decision is yours if you still think those malware files you want to re-use for any purpose then sole it's your decision and you have been made aware of abuse fee and warned about issue case may repeat again if reused the same files as required.