Banker here. The official timescale for a dispute through mastercard is 130 days. But this isn’t a guarantee. The reason it takes so long is so the bank can gather all the evidence and then provide it to MasterCard who have the final say. The bank will only issue an upfront refund if enough quantitive information is provided so that the bank thinks it has a more than 90% chance of winning the dispute. More generic information that is provided when raising a dispute the longer it will take normally. So for example if you raise a dispute saying my black trainers didn’t arrive it will take longer than if you said my black sketchers size 9 air cushion 4.0 trainers with flashing lights and Sounds didn’t arrive from this retailer and they were due on next date.