What does 'chop and change' mean?

anne's craft goods

123 e mason drive, johnson, ms

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to whom may it may concern;

i have recently ordered a product from your online shop. the shipping details read that my order would be delivered by the 8th of december, whereas it was delivered the 13th. i needed the package for a christmas exchange. 

since i paid for overnight shipping, but did not receive the package in the time allotted, i am kindly asking for a refund. the product was just perfect, but i do not believe i should have to pay for a quick shipping if it came late.

you for your time, i hope to hear from you soon.

sincerely,

john smith