I am going through this now so want to share some advice. You can request an appeal and they will review the case. If they feel they are in the right they will keep the ban/sanction and any future Comms you have with them (either on web chat or by emailing a case) will be deleted. If you ask to escalate a complaint they will delete it, if you ask what the escalation policy is they will claim there is nothing more than can do.
If you feel you have done nothing wrong you can try mailing their legal team at:
Legal team
Electronic Arts Limited, Onslow House, Onslow Street, Guildford, Surrey GU1 4TN
When I asked the online help why they didn't tell me about this they pretending they had forgotten and then apologised. Do not expect any transparency and they will do everything they can to not engage in due process.
Hope that helps
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