SFR 3G internet clé help

I'm sorry if this duplicates existing info, but I've searched on the forums and can't find the topic.

Basically, we aren't living in France full-time and don't want to pay for a phone line in order to have internet. I bought a SFR 3G internet clé (pay as you go) in August, which worked fine until the credit ran out .... Now I cannot top it up! I cannot top up online because I can't create a user account (I've never received a password, which they say will be sent by SMS to the dongle, but never does). I can try going into our local mobile phone shop, which is an SFR agent, but it's not the shop where we bought the device. My French isn't brilliant, but a French speaking friend went through the online help features on the SFR website without getting anywhere. Before I tackle the shop and/or the SFR phone support, does anyone have any knowledge or experience of this product?

I know these aren't the most economical options, I have a smartphone with an Italian SIM but it also seems an expensive option. If anyone has a better idea I'd be very grateful.