RCA 9'' charging port...big probs

I now have acquired 3 RCA 9'' tablets that is such a pain in the *** to fiddle with the port to have them 'finally' '''catch''' to charge.
I have bought two of these brand new.... one for me.... one for my daughter....and the third was given to me brand new.
It's driving me crazy!!! I have been learning patience with trying to just get the charger endy thing that fits in the tablet port to charge the darn thing. AND.... the patience that I have learned is dwindling......fast.
Is there any way that I can get this fixed or a trick that I haven't figured out yet? I have tried different chargers.......different outlets........different outlets/chargers......sticking my tongue out to the left...... sticking my tongue out to the right ...... I cannot get the charging endy thing to 'catch' on the charging port (if that is what the problem is.) I have narrowed it down to that. I think.
Please oh please.....help. I've had these for almost a year now...so I'm assuming that I cannot just take them back and exchange them for ..... ( more than likely the same prob.)
I would like to be able to fix this quick, easy and cheap. :banghead
THANKS!