Have I wasted my money on lower implants for a denture?

Q. I have lower implant for a denture. The o rings have been replaced many times because the plate gets loose and flops around. I paid thousands of dollars for this thinking I would always have a secure denture. Now I am told that these rings need to be replaced every 6 mos at a cost to me. Now therings don’t even last a month. I was also told it is what I eat that could be the problem. I chose this route of denture replacement because I wanted to resume my normal eating habits, which include corn on cob, steak, nuts, gum. Now to be told this is my problem, I should have gone the simple denture route. I have little jaw and also this is my problem. I have no problems with the abuttments, just the denture plate. Any suggestions, or did I throw 7 grand to the wind or someones vacation. I have only had this for 3 years…..