You should really be careful about swallowing the whole Murabitun party line. Don't assume any one group has all the answers to the questions. A great shaykh once said "Every group has some good; take it and gather it all in within yourself." The hatred of Riba that the Murabitun have is good, their methods are a bit odd, and their Shaykh is not qualified at all, so be careful and take from them the good and do not become like the same as the rest of them are... Just some brotherly naseehah.