Estimates provided by ebay are INCORRECT and can often be shown as next day and even in some cases same day delivery which is simply not possible.
Please be aware that orders are shipped via Evri on Monday, Wednesday and Friday mornings with orders cutoff at midnight the night before.
Estimated shipping time from that point would be approximately 3 days depending on location.
For example:
Orders placed on Friday at 10am would be shipped Monday morning with an estimated delivery of Wednesday/Thursday depending on location.