Delete table then table pops up again (deletion nearly not possible)

Hi all, I have a big problem. I have several CSV/xlsx-filles uploaded as tables to my data model. When I try to delete one table (e.g. in data model under Tables) I click in Edit and then Remove table. After done that the table is gone, but ca. 10-12 seconds later the table comes back, magic. If I click it several times, sometimes the table is gone then. At the buttom of the Tables list there are then created several new tables like that Auswahl_Delta.xlsx_0_0_0_2_0_1_0_0_0_0_0_2 What can I do to solve that? What is going wrong? Please help me. Thx and br Daniel