I get phone numbers while shopping, etc (e.g. by asking if she'd like coffee later the week, and if yes, whats her number?) . Then within a week timeframe, sometimes the next day, I send them an invite via whatsapp for coffee or lunch.
They then do not answer. Why is this? Why do they give me their number if they don't want to follow up?
Another problem I have encountered is that girls in gym don't give out their numbers and often dont like to be picked up while exercising.