Mase -- Allegedly Ducking Five Figure Jewelry Tab

Getting sued for $35,000 definitely does not feel so good to rapper Mase -- especially when he claims he doesn't even have any obligation to pay the money in the first place!

Mase has been fighting an ongoing legal battle with Aydin and Company, a jeweler in Atlanta, since the summer. According to legal docs filed in Georgia, they claim Mase owes them $35,000 dating alllllll the way back to 2005.

According to court filings, the jewelers haven't been able to serve Mase with legal papers after trying multiple times at his Georgia home -- each time being turned away by staff who say he isn't there. They claim he's been ducking them for months and they had a process server file an affidavit in the case ... stating Mase is "evading service."

For his part, Mase filed papers asking for the suit to be dismissed ... claiming improper service and the fact that he never signed the "alleged contract at issue in case."

The jewelers want their money, attorneys fees and 1.5% interest per month on the money he owes.