oven comes on to temp but will not reheat to a new temp third time trouble with same range

first of all i have one advantage even though i am 70 yrs old i had a appliance shop for sears in the 60s and 70s and have not forgotten to much of the basics i am still in the security business and up on electronics. last time i had the company repair the oven , 70 dollars for the part 75 dollars for the svs call. (first igniter was on full warranty) well this time i decided to look for trhe part myself, i just went on line typed in oven repair parts and eventually all these sites came up. yours was the most professional looking and i took a chance. guess what everything you promised you delivered. price quality USA made parts and delivered in three days . opened package went to work less than fifteen minutes back in business.
will sure use you again if the need arises thank you