I would first wonder why they determined that you are not responsive to the tetanus shot. I suspect they measure antibody levels and found that yours were low. This, in itself, does not mean that you are unresponsive to the tetanus shot.
To truly determine this, your antibody levels must be low then you should receive a booster dose of the tetanus vaccine. 2 weeks later, your antibody levels should be tested again.
The tetanus antibody levels normally fall in the body producing the need for boosters.
I'm not sure I would recommend that you not get anymore tetanus vaccines at this point.
Advice and opinions given are based on the information provided and must not be considered an official medical recommendation. The limitations of the internet prevent an appropriate evaluation. Always consult your doctor if there is concern.