AFS Ltd. - Malta

About a year and a half ago, I bought 2 water tanks from AFS in Attard. After the first year I started noticing that both tanks were changing shape, at first I did not really bother. The problem came when I tried to open and close the water tank lid, by than the tank was so bad that I could not close the lid since it became oval.
When I asked about this problem to the lady at AFS she said that this was the first time that they heard about a tank changing shape!!!!!!, well this was not true EVEN their technician said that this has happened many times before.
To cut a long story short.... They sent the technician and he told me that unless the tank is punctured than they will not fix or replace, he also mentioned that in Malta we have very strong hot summer and this was the main problem.
Last thing: I returned to the shop after some weeks and the lady said that the Factory in Italy closed and that she could do nothing.

no.1: I bought in Malta and I expect it to be resistant for our climate.
no.2 : It is suppose to be 15 years Guarantee
no.3 : Why did she say that I was the first to complain on tank changing shape when its a known fact that their tanks are of poor quality and they change shape.
no.4 : Now that the factory closed down AFS shouldn’t be responsible.

I have heard many complains about AFS Best thing is to keep away

Thanks