New Hot End - WRONG SIZE!

Decided that a spare hot end should be on hand so ordered one from China.   Takes a while to get by which time my current hot end has become clogged.   I need that spare.   I go to install it so I can clean the original and ALAS it is a 3mm hot end not a 1.75mm!  Doop.   Have had great luck working with vendors in China so am sure I will get this resolved but the timing is a challenge.