Ok a bit of background

about 5-6 weeks ago wife sold her iPhone 6 on FB - She accurately described the phone in the ad as in working order with 78% battery life and that it did not come with charger or cable

a lady buys phone and picks it up - all good so far

2 days later lady sends a message that the phone is stuffed, doesn't work properly, constantly needs to be charged and the battery needs to be replaced - wants money back.

we replied that the phone was in working condition and reminded her of the battery life as per the ad

long story short, this woman is harassing us - demanding at least half of her money back... she is messaging us regularly saying we have 'scammed' her - which is totally incorrect. after replying to the first few of her messages, we have now taken to just ignoring her

I thought I'd managed to block her from FB, but then another message came in this morning that contained several 'F' words... I didn't read the message fully, but needless to say it was not polite!

I've gone in to the messages, right clicked on her name and removed myself from the conversation.... but I'm not exactly sure what this does, or if the woman can still send us messages or not.

is there anything else we can do to stop this woman sending us messages?

any advice would be helpful