Lost Backup Data

Since 7years I was using iCloud account, from last 3years I was not using iphone but I was paying every month 1USD to maintain my backup, today I bought new iphon, when I try to restore my previous data from icloud I couldn't find device name on iCloud account, it was showing there no backup available, you can set up as new iphone. but when I logged in to iCloud account on PC 19GB data backup can see on iCloud but on 2018 my backup data was more than 34GB I don't know where it's gone rest of my 14GB data. I talked to support team in india but their response was If our iCloud account not syncing more than 6month previous device name will automatically deleted by apple but photos and documents will be there. Is that true?