Rediator for 1400 Nissan

Please be careful when buying radiators from Corenet Radiators. We have recently overhauled 2 x Nissan 1400 LDV,s for a Courier company and we did replace the radiators as well. First off all the one radiator started leaking about 2 weeks ago and we replaced it. The other radiator radiator started to leak during the course of this week. I phoned Jannie and Anton from Corenet and explained the situation to them. The first answer that i got was that its either the vehicle is overheating or there must be an electric current running trough the radiator. This diagnoses where **** without seeing the radiators. I asked them to please assist and they offers me a radiator at almost retail. I feel that this is not acceptable as the radiator is less than 2 weeks old and that they should have at least had it checked out before the reason for the damaged radiator where pre-judged.