Would like to know why i am still getting some messages that are garbled , after i have done everything ?

was getting some messages from yahoo groups that where garbled and i have done everything to try to correct this. Not my server but I changed all my email addys, when i tried gmail i did not get any. but did not like it so i changed back, and here we go again, they started to come in. Even changed my yahoo addy and still did not work so it has to be yahoo server, would like my answer to my question or any help to go to mybuddy2002@cogeco.ca thanks