If you have a US address, just figure out who your congressional representative is. I think one of the congress websites has a tool to find that out, if you don't already know. I'm not sure how it works if you're outside the US with no US address. You must still have a representative? Anyway, all the people in congress have a website, and on those sites there's a link to send them an inquiry. When you do that, there's some questions you have to answer. What kind of problem you're having, what agency is involved, etc. Then, there's a box for you to explain your problem. When you do that, keep it simple and to the point, but do give them the necessary information. Your Civil Service Claim No., the months you did not receive payments, the bank that's supposed to receive them, including the account number and routing number. With all that information, they should easily be able to figure out what happened to your payments for the missing months. For what it's worth, I did finally receive my missing payment to the correct account, three or four days after I sent the inquiry. So OPM must have someone paying attention to the inquiries.