Buyer doesn't know English well.
Expects something which he hasn't been promised.
After not getting which he hasn't been promised he starts complaining.
Uses slang, as he must have been homeschooled.
Or belong to a slangy family or have been grown up on such on or had none or a street kid.
Beware of this buyer. He will be expecting a guarantee after delivery, which you don't provide and ask for a refund of something which you.
Thus he makes you work for him and takes the refund and eventually will make you work for free.
It has, check on the first paragraph.
Thank you so much sir
Looking forward to work with you again
Thank you for your order, GoodLuck and waiting for the next order