There is a two day lag between the first available day to purchase Premier Club last year and the first available day to purchase Premier Club this year.
This means that anybody who purchased Premier Club within the first two days last year and intends to purchase again this year will have up to two days without Premier Club membership and those extra bank spaces will be unavailable for that period of time.
This is unfortunate, sorry.
"Also if i was a gold member and it ran out how am i still a member. not right."
You must have had some residual regular membership sitting there waiting to be used up.
Note: Premier Club has been part of Runescape for eight years. 2021 will be the ninth year.