piglet it is perfectly possible to induce lactation for twins, but it's seriously, seriously hard work and doesn't work for everyone. Claire B-C's statements that some women feel terrible if BFing doesn't work for them is absolutely true, of course it is, and that's a terrible, awful thing. That is precisely why people dedicate their time, often unpaid, often in the face of abuse, to supporting mothers who want to breastfeed so that they don't need to feel like that.
C B-C on the other hand writes book within which she offers advice which actively undermines breastfeeding. She causes women to not be able to breastfeed, then tells them not to feel guilty about it. THAT is why she makes no sense.
You will find loads of support here, and as has been suggested at a local breastfeeding group. Keep the breastfeeding lines to hand as they're looked after by fully qualified breastfeeding counsellors (they may not be at a group). It's also worth seeing if you have a local LLL, ABM, BfN or NCT group nearby and whether they have a breastfeeding counsellor who you can call upon if needed.
Low supply can be caused by rare physical conditions, but is more likely to be because the baby isn't put to the breast often enough, or, when baby is feeding he's not doing so efficiently due to poor attachment (which may be easy to fix or maybe something a bit harder like tongue tie). While many, many women believe they have low supply, in fact they either don't, and they're just not expecting a baby to feed so often, or they could rectify it with a bit of help.
Because a well-latched baby is more efficient at removing milk (and therefore telling your body to make more milk) than a pump, relying on a pump to increase supply can be more work and stress than help. While it is a useful tool for some cases it's very much not the first one to turn to.
Pumps are ace for mums who need to be separated from their baby, for mums donating to milk banks, mums wanting to express for older children, and so on. But rarely are they the best first tool for supply queries :)