A few unfriendly cashiers in need of some training?

I previously sent an email mentioning that some of the cashiers at Norwood Spar would greatly benefit from some training regarding 'Greeting', saying 'Please and Thank You' and in general just being friendlier. The store manager (unfortunately forgot the name) did contact me at the time, and I said I would report back if i notice a change. Sadly, a few months later, the is still one cashier (Coloured lady with orange hair) and Dawn, the white lady, who are not getting it right. They don't great, let a lone saying 'Please' or 'Thank You'. I will in future let the next person in line go ahead of me, if I see that the till of one of these two ladies opens up. Other customers might be mope comfortable with this unfriendly attitude of these two ladies, not I.