can my truck be repossessed if the title is legally in my name?

[vtec_power_88]

i bought a truck from my ex girlfriends dad i told him id get him on the next paycheck well that didnt happen i got laid off and and he said that ok and singed it over and told me to pay him asap that was in august hes been texting me asking if i got a job yet and if i have his money i plan to pay him but i just want to know if he can do anything legally like call the cops or get a lawyer since its legally in my name