Powerbank not loaded on slip with upgrade as promo

Went for my upgrade Tuesday 7 July and selected the powerbank as the promoted \get any of these gifts with these deals"gift during the upgrade process. Was then told they don't have it in stock now so they will let me know when I can collect. My sim swop only took place 2 and a half days AFTER I called the store to enquire. Was told they received powerbanks so I could come collect. Went back Friday night only to be told that my upgrade wasn't rung up with the free gift up on my contract's paperwork so they can't be of ANY assistance to correct Wesley's mistake but I should come back again Saturday to discuss with the store manager. Acting store manager Michelle Williams (there Tuesday and Friday) wasn't in the least bit interested resolving your consultant's error and just kept saying my upgrade was on old contract and the promotion only started from 8 July (without even looking at any of my paperwork). I went back to the store today being Saturday when manager Izanette would be in as per Bianca (who explained on Friday night everything that the sales consultant did wrong but with no solution for fixing the error. Izanette was not in and Michelle only gave complaints tel. nr."""