The offer of a replacement seems to be a new scam from sketchey sellers, mostly Chinese but it will spread.
Since the original item did not arrive within 45 days,why would the replacement arrive on time?
Frankly, since the international postal system is very reliable, I doubt anything was sent in the first place.
In future, if offered a replacement, ask for a full refund instead. Then, if you still trust the seller, re-order the item and hope that it will arrive within deadline.