Since 2 weeks I'm unable to send BTC in my multibit wallet to my own bitstamp a/c, so that I could sell the BTC from there.
I have the multibit wallet since end 2013 (version 0.5.14).
The multibit site doesn't let me paste/drag the destination address nor the QR I received from bitstamp into the appropriate window - I have to type it in manually, the invariably a 'Invalid address!' message pops up.
I've posted varioius messages to multibit support over the last week, and have not received any answer
(so much for customer service at multibit).

Multibit also doesn't tell me what their fee is to make the transfer, and how I can pay for it - e.g. leaving some BTC in the wallet?

I'm very frustrated and would be very grateful for help!