I just got approved "fully favorable" for disability. I am 46 and under my husbands insurance, so I don't need part B right now and they will be taking $99 a month from my SSDI payment. I wrote SS office and sent in the notice to opt out. How long will this take and will they reimburse me for the money thet have taken? I got approved at end of May and the are charging me back since January this year. Also, how long before my back pay comes. I appreciate any and all responses. Thanks so much to you all. Jules