Hi!
It looks like the container does not respond as it should. In these cases I usually suggest a custom CSS to force a certain width on the elements on different screen sizes, something like this:
@media only screen and (max-width: 768px) {
.rpp_item {
width: 33% !important;
}
}
@media only screen and (max-width: 600px) {
.rpp_item {
width: 50% !important;
}
}
@media only screen and (max-width: 380px) {
.rpp_item {
width: 100% !important;
}
}