Trekit 365 worst ever

Worst company ever.Due to non payment from my side had personal issues with work and salary I communicated with them regarding payment.Then boom today they switch my cars off one car was driving on the N2 when they switched it off almost caused a big accident.My question is are they in their rights to switch my cars off because nowhere in my contract does it states that they will or may do that.Ive asked the consultant where in the contract does it state that they may switch my car off and she couldn't answer me because nowhere does it state that they may or will do it when they don't receive payment.Where can I lay a complaint again this company