@saosisbiotech...
Ebay has fixed time schedules for their categories and all sellers have to act within those guidelines. If you want to go beyond those timelines then you will have to ask the buyer for "Time Extension". Your delivery schedule is your problem not ebay's problem. Ebay is not under any obligation whatsoever to listen to you. Would advice you to read the seller guide before selling on ebay.
Please do not use terms like
"Please tell me what should be my next action against ebay if THEY DO NOT COMPLY WITH MY REQUEST?". Ebay is not doing any injustice to you that you want to take action aganist ebay.
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